Examples with solutions for Solving an Equation by Multiplication/ Division: Solving an equation with fractions

Exercise #1

4=3y 4=3y

Video Solution

Step-by-Step Solution

The goal is to solve the equation 4=3y 4 = 3y to find the value of y y . To do this, we can follow these steps:

  • Step 1: Divide both sides of the equation by 3 to isolate y y .
  • Step 2: Simplify the result to solve for y y .

Now, let's work through the solution:

Step 1: We start with the equation:

4=3y 4 = 3y

To solve for y y , divide both sides by 3:

y=43 y = \frac{4}{3}

Step 2: Simplify the fraction:

y=43=113 y = \frac{4}{3} = 1 \frac{1}{3}

Therefore, the solution to the equation is y=113 y = 1 \frac{1}{3} .

This corresponds to choice y=113 y = 1\frac{1}{3} in the provided multiple-choice answers.

Answer

y=113 y=1\frac{1}{3}

Exercise #2

6x=12.6 6x=-12.6

Video Solution

Step-by-Step Solution

To solve the equation 6x=12.66x = -12.6, we need to isolate xx. We achieve this by performing the following steps:

  • Step 1: Identify the coefficient of xx, which is 66. We aim to isolate xx by dividing both sides of the equation by 66.
  • Step 2: Divide both sides of the equation by 66 to solve for xx. This will eliminate the coefficient and reveal the value of xx.

Let's perform these calculations:

6x6=12.66\frac{6x}{6} = \frac{-12.6}{6}

Simplifying both sides gives:

x=2.1x = -2.1

Therefore, the solution to the equation is x=2.1\boldsymbol{x = -2.1}.

Answer

x=2.1 x=-2.1

Exercise #3

y5=25 \frac{-y}{5}=-25

Video Solution

Step-by-Step Solution

We begin by multiplying the simple fraction by y:

15×y=25 \frac{-1}{5}\times y=-25

We then reduce both terms by 15 -\frac{1}{5}

y=2515 y=\frac{-25}{-\frac{1}{5}}

Finally we multiply the fraction by negative 5:

y=25×(5)=125 y=-25\times(-5)=125

Answer

y=125 y=125

Exercise #4

3b=76 3b=\frac{7}{6}

Video Solution

Step-by-Step Solution

To solve the equation 3b=76 3b = \frac{7}{6} for the variable b b , we will perform the following steps:

  • Step 1: Identify the equation. The given equation is 3b=76 3b = \frac{7}{6} .
  • Step 2: Isolate the variable. Divide both sides by 3 to solve for b b .

When we divide both sides of the equation by 3, we obtain:

b=763 b = \frac{\frac{7}{6}}{3}

Step 3: Simplify the expression. Dividing a fraction by an integer is equivalent to multiplying the denominator of the fraction by that integer:

b=76×3 b = \frac{7}{6 \times 3}

The denominator becomes:

b=718 b = \frac{7}{18}

Thus, the solution to the equation is b=718 b = \frac{7}{18} .

This matches the correct answer choice among the given options.

Therefore, the value of b b is b=718 b = \frac{7}{18} .

Answer

b=718 b=\frac{7}{18}

Exercise #5

3x4=16 \frac{3x}{4}=16

Video Solution

Step-by-Step Solution

To solve the equation 3x4=16\frac{3x}{4} = 16, we will eliminate the fraction by multiplying both sides by 4.

  • Step 1: Multiply both sides by 4:
    (3x4)×4=16×4\left(\frac{3x}{4}\right) \times 4 = 16 \times 4
  • Step 2: Simplify:
    3x=643x = 64
  • Step 3: Solve for xx by dividing both sides by 3:
    x=643x = \frac{64}{3}
  • Step 4: Simplify the fraction to a mixed number:
    x=2113x = 21\frac{1}{3}

Therefore, the solution to the equation 3x4=16\frac{3x}{4} = 16 is x=2113 x = 21\frac{1}{3} .

Answer

x=2113 x=21\frac{1}{3}

Exercise #6

4x6.9=2.2x+5 4x-6.9=2.2x+5

Video Solution

Step-by-Step Solution

To solve this problem, follow these steps:

  • Step 1: Identify the equation and its components. The equation is 4x6.9=2.2x+54x - 6.9 = 2.2x + 5.
  • Step 2: Move the terms involving xx to one side of the equation. Subtract 2.2x2.2x from both sides:
    4x2.2x6.9=54x - 2.2x - 6.9 = 5.
  • Step 3: Combine like terms on the left side:
    1.8x6.9=51.8x - 6.9 = 5.
  • Step 4: Move constant terms to the other side by adding 6.96.9 to both sides:
    1.8x=5+6.91.8x = 5 + 6.9.
  • Step 5: Simplify the equation on the right side:
    1.8x=11.91.8x = 11.9.
  • Step 6: Solve for xx by dividing both sides by 1.81.8:
    x=11.91.8x = \frac{11.9}{1.8}.
  • Step 7: Simplify the fraction if possible:
    Converting 11.91.8\frac{11.9}{1.8} to a mixed number, x=61118x = 6\frac{11}{18}.

Therefore, the solution to the equation is x=61118x = 6\frac{11}{18}.

Answer

x=61118 x=6\frac{11}{18}

Exercise #7

a6=67 \frac{a}{6}=\frac{6}{7}

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Start with the given equation.
  • Step 2: Use cross-multiplication to eliminate the fractions.
  • Step 3: Simplify the resulting expression.
  • Step 4: Solve for the variable a a .

Now, let's work through each step:
Step 1: The equation given is a6=67 \frac{a}{6} = \frac{6}{7} .
Step 2: We apply cross-multiplication: Multiply both sides to get a×7=6×6 a \times 7 = 6 \times 6 .
Step 3: Simplify the equation: 7a=36 7a = 36 .
Step 4: Solve for a a by dividing both sides by 7:
a=367 a = \frac{36}{7} .
This fraction can be converted to a mixed number: a=517 a = 5\frac{1}{7} .

Therefore, the solution to the problem is a=517 a = 5\frac{1}{7} .

Answer

a=517 a=5\frac{1}{7}

Exercise #8

Solve for X:

x57=211 \frac{x-5}{7}=\frac{2}{11}

Video Solution

Step-by-Step Solution

To solve x57=211 \frac{x-5}{7} = \frac{2}{11} , we will use cross-multiplication:

  • Step 1: Cross-multiply the equation: (x5)×11=7×2 (x-5) \times 11 = 7 \times 2 .
  • Step 2: Simplify both sides: 11(x5)=14 11(x - 5) = 14 .
  • Step 3: Distribute the 11 on the left side: 11x55=14 11x - 55 = 14 .
  • Step 4: Add 55 to both sides to isolate the 11x 11x term: 11x=14+55 11x = 14 + 55 .
  • Step 5: Calculate the right side: 11x=69 11x = 69 .
  • Step 6: Divide both sides by 11 to solve for x x : x=6911 x = \frac{69}{11} .

Therefore, the solution to the problem is x=6911 x = \frac{69}{11} , which matches the first answer choice provided.

Answer

6911 \frac{69}{11}

Exercise #9

Solve for X:

x+23=45 \frac{x+2}{3}=\frac{4}{5}

Video Solution

Step-by-Step Solution

To solve the equation x+23=45 \frac{x+2}{3}=\frac{4}{5} , we can follow the method of cross-multiplication:

  • Step 1: Cross-multiply to eliminate the fractions, giving us:

(x+2)5=43(x + 2) \cdot 5 = 4 \cdot 3

  • Step 2: Simplify both sides of the equation:

5(x+2)=125(x + 2) = 12

  • Step 3: Distribute the 5 on the left side:

5x+10=125x + 10 = 12

  • Step 4: Subtract 10 from both sides to isolate the term with x x :

5x=25x = 2

  • Step 5: Divide both sides by 5 to solve for x x :

x=25x = \frac{2}{5}

Therefore, the solution to the equation is 25 \frac{2}{5} .

Answer

25 \frac{2}{5}

Exercise #10

Solve for X:

x418=79 \frac{x-4}{18}=\frac{7}{9}

Video Solution

Step-by-Step Solution

To solve the equation x418=79 \frac{x-4}{18} = \frac{7}{9} , we'll follow these steps:

  • Step 1: Apply the principle of cross-multiplication to eliminate fractions.

  • Step 2: Solve for the linear expression in terms of x x .

  • Step 3: Isolate x x and solve the equation completely.

Now, let's work through each step:
Step 1: Cross-multiply to eliminate the fractions. The equation becomes:

(x4)9=1879(x4)=126 (x-4) \cdot 9 = 18 \cdot 7 \\ 9(x-4) = 126

Step 2: Distribute the 9 on the left-hand side:

9x36=126 9x - 36 = 126

Step 3: Add 36 to both sides to isolate the term with x x :

9x=126+369x=162 9x = 126 + 36 9x = 162

Step 4: Divide both sides by 9 to solve for x x :

x=1629x=18 x = \frac{162}{9} \\ x = 18

Therefore, the solution to the equation is x=18 x = 18 .

Answer

18 18

Exercise #11

70=412b 70=4\frac{1}{2}b

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Convert the mixed number to an improper fraction
  • Step 2: Isolate b b using multiplication
  • Step 3: Simplify to find the value of b b

Now, let's work through each step:

Step 1: Convert 412 4\frac{1}{2} to an improper fraction:

412=92 4\frac{1}{2} = \frac{9}{2}

Step 2: Isolate b b on one side of the equation:

The equation becomes 70=92b 70 = \frac{9}{2}b

To isolate b b , multiply both sides by the reciprocal of 92 \frac{9}{2} :

b=70×29 b = 70 \times \frac{2}{9}

Step 3: Perform the multiplication:

b=70×29 b = \frac{70 \times 2}{9}

b=1409 b = \frac{140}{9}

The improper fraction 1409 \frac{140}{9} converts to a mixed number:

b=1559 b = 15 \frac{5}{9}

Therefore, the solution to the problem is b=1559 b = 15\frac{5}{9} .

Answer

b=1559 b=15\frac{5}{9}

Exercise #12

Solve for X:

x+43=78 \frac{x+4}{3}=\frac{7}{8}

Video Solution

Step-by-Step Solution

First, we cross multiply:

8×(x+4)=3×7 8\times(x+4)=3\times7

We multiply the right section and expand the parenthesis, multiplying each of the terms by 8:

8x+32=21 8x+32=21

We rearrange the equation remembering change the plus and minus signs accordingly:

8x=2132 8x=21-32
Solve the subtraction exercise on the right side and divide by 8:

8x=11 8x=-11

8x8=118 \frac{8x}{8}=-\frac{11}{8}

Convert the simple fraction into a mixed fraction:

x=138 x=-1\frac{3}{8}

Answer

138 -1\frac{3}{8}

Exercise #13

Solve for X:

5x8=34x \frac{5}{x-8}=\frac{3}{4x}

Video Solution

Step-by-Step Solution

To solve the equation 5x8=34x \frac{5}{x-8} = \frac{3}{4x} for the variable x x , we will follow these steps:

Step 1: Apply cross-multiplication to the equation. This involves multiplying the numerator of each fraction by the denominator of the other fraction:

54x=3(x8) 5 \cdot 4x = 3 \cdot (x - 8)

Step 2: Simplify both sides of the resulting equation:

20x=3x24 20x = 3x - 24

Step 3: Rearrange the equation to isolate terms involving x x on one side:

20x3x=24 20x - 3x = -24

This simplifies to:

17x=24 17x = -24

Step 4: Solve for x x by dividing both sides of the equation by 17:

x=2417 x = \frac{-24}{17}

Therefore, the solution to the equation is:

x=2417 x = \frac{-24}{17}

Answer

2417 \frac{-24}{17}

Exercise #14

Solve for X:

58x=32x \frac{5}{8-x}=\frac{3}{2x}

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Identify that the given equation is 58x=32x\frac{5}{8-x} = \frac{3}{2x}.
  • Step 2: Cross-multiply to eliminate the fractions.
  • Step 3: Solve the resulting linear equation.
  • Step 4: Check for any restrictions on xx.

Now, let's work through each step:

Step 1: We have the equation:

58x=32x\frac{5}{8-x} = \frac{3}{2x}

Step 2: Cross-multiply to get:

52x=3(8x)5 \cdot 2x = 3 \cdot (8-x)

This simplifies to:

10x=243x10x = 24 - 3x

Step 3: Solve for xx by isolating it on one side of the equation. Add 3x3x to both sides:

10x+3x=2410x + 3x = 24

This simplifies to:

13x=2413x = 24

Now, divide both sides by 13:

x=2413x = \frac{24}{13}

Step 4: Verify that this value does not make any of the original denominators zero. For x=2413x = \frac{24}{13}, the terms 8x8-x and 2x2x are well-defined, and neither is zero:

82413=80132413=561308 - \frac{24}{13} = \frac{80}{13} - \frac{24}{13} = \frac{56}{13} \neq 0

2×2413=481302 \times \frac{24}{13} = \frac{48}{13} \neq 0

No issues arise from substituting back, so our solution is valid.

Therefore, the solution to the problem is x=2413 x = \frac{24}{13} , which corresponds to choice 3.

Answer

2413 \frac{24}{13}

Exercise #15

Lionel buys x x packs of paper.

The price of each pack is 4.5andhepaysatotalof4.5 and he pays a total of 45.

Calculate x x .

Video Solution

Step-by-Step Solution

To solve this problem, we'll use a step-by-step approach:

Step 1: Set up the equation based on the problem statement.
The total cost Lionel pays is given by the formula:

4.5x=45 4.5x = 45

Here, x x is the number of packs Lionel buys, and $4.5 is the cost per pack.

Step 2: Solve for x x .
To find x x , divide both sides of the equation by 4.5:

x=454.5 x = \frac{45}{4.5}

Step 3: Perform the division.
Carrying out the division,

x=454.5=10 x = \frac{45}{4.5} = 10

Therefore, Lionel buys x=10 x = 10 packs of paper.

Answer

x=10 x=10

Exercise #16

Solve for x:

8x45=2x+24 \frac{8x-4}{5}=\frac{2x+2}{4}

Video Solution

Step-by-Step Solution

To get rid of the fraction mechanics, we will cross multiply between the sides:

4(8x4)=5(2x+2) 4(8x-4)=5(2x+2)

We expand the parentheses by multiplying the outer element by each of the elements inside the parentheses:

32x16=10x+10 32x-16=10x+10

We arrange the sides accordingly so that the elements with the X are on the left side and those without the X are on the right side:

32x10x=10+16 32x-10x=10+16

We calculate the elements:

22x=26 22x=26

We divide the two sections by 22:

22x22=2622 \frac{22x}{22}=\frac{26}{22}

x=2622 x=\frac{26}{22}

Answer

2622 \frac{26}{22}

Exercise #17

Solve for X:

8+x3=x+49 \frac{-8+x}{3}=\frac{x+4}{9}

Video Solution

Step-by-Step Solution

To solve for x x in the equation 8+x3=x+49\frac{-8+x}{3}=\frac{x+4}{9}, we'll follow these steps:

  • Step 1: Eliminate the fractions by finding a common denominator.
  • Step 2: Simplify the resulting equation.
  • Step 3: Isolate x x to solve the equation.

Let's proceed step by step:

Step 1: The equation 8+x3=x+49\frac{-8+x}{3}=\frac{x+4}{9} contains denominators 3 and 9. The least common denominator (LCD) is 9. To eliminate the fractions, multiply every term of the equation by 9.

9×8+x3=9×x+499 \times \frac{-8+x}{3} = 9 \times \frac{x+4}{9}

Simplifying, we have:

3(8+x)=x+43(-8 + x) = x + 4

Step 2: Distribute the 3 on the left side:

3×8+3×x=x+43 \times -8 + 3 \times x = x + 4

This simplifies to:

24+3x=x+4-24 + 3x = x + 4

Step 3: Isolate x x . First, subtract x x from both sides of the equation:

24+3xx=x+4x-24 + 3x - x = x + 4 - x

This simplifies to:

24+2x=4-24 + 2x = 4

Next, add 24 to both sides to further isolate x x :

24+24+2x=4+24-24 + 24 + 2x = 4 + 24

This simplifies to:

2x=282x = 28

Finally, divide both sides by 2 to solve for x x :

x=282x = \frac{28}{2}

Simplifying this gives:

x=14x = 14

Therefore, the solution to the equation is x=14 x = 14 .

Answer

14 14

Exercise #18

Solve for X:

5x8=3+x2 \frac{5-x}{8}=\frac{3+x}{2}

Video Solution

Step-by-Step Solution

To solve the equation 5x8=3+x2 \frac{5-x}{8} = \frac{3+x}{2} , we will follow these steps:

  • Step 1: Eliminate the fractions by cross-multiplying.
  • Step 2: Simplify the resulting equation.
  • Step 3: Solve for x x .

Let's proceed with each step:

Step 1: Cross-multiply.
Cross-multiplying gives:

(5x)×2=(3+x)×8(5 - x) \times 2 = (3 + x) \times 8

Which simplifies to:

2(5x)=8(3+x)2(5 - x) = 8(3 + x)

Step 2: Expand and simplify.
Distribute the constants inside the parentheses:

102x=24+8x10 - 2x = 24 + 8x

Step 3: Isolate x x .
Add 2x 2x to both sides to bring all terms involving x x to one side:

10=24+10x10 = 24 + 10x

Subtract 24 from both sides to isolate the term with x x :

1024=10x10 - 24 = 10x

Simplify:

14=10x-14 = 10x

Finally, divide both sides by 10 to solve for x x :

x=1410x = \frac{-14}{10}

Therefore, the solution to the problem is x=1410 x = \frac{-14}{10} , which corresponds to choice .

Answer

1410 \frac{-14}{10}

Exercise #19

1 kg of tomatoes costs 2.8.<br><br>Maggiebuys2kgoftomatoesand0.6kgofcucumbers,costingatotalof2.8.<br><br>Maggie buys 2 kg of tomatoes and 0.6 kg of cucumbers, costing a total of 7.1.

Express the value per kg of cucumbers in terms of x x (in dollars).

Video Solution

Step-by-Step Solution

To solve for the price per kg of cucumbers, follow these steps:

  • Step 1: Determine the total cost of tomatoes.
    Given that the cost of tomatoes is 2.8 per kg, and Maggie buys 2 kg, the cost of tomatoes is calculated as:
    \( 2 \, \text{kg} \times 2.8 \, \text{dollars/kg} = 5.6 \, \text{dollars} .

  • Step 2: Write the equation for total cost.
    The total cost for tomatoes and cucumbers combined is given as 7.1. Let \( x represent the cost per kg of cucumbers. The equation representing the total cost is:
    5.6+0.6x=7.1 5.6 + 0.6x = 7.1 .

  • Step 3: Solve the equation for x x .
    Subtract the cost of tomatoes from both sides of the equation to find the cost of cucumbers:
    0.6x=7.15.6 0.6x = 7.1 - 5.6 .
    Simplifying the right side gives:
    0.6x=1.5 0.6x = 1.5 .

  • Step 4: Isolate x x by dividing both sides by 0.6:
    x=1.50.6 x = \frac{1.5}{0.6} .
    Simplify the division to find x x :
    x=2.5 x = 2.5 .

Therefore, the value per kg of cucumbers is x=2.5 x = 2.5 dollars.

Answer

x=2.5 x=2.5