Examples with solutions for Solving an Equation by Multiplication/ Division: Addition, subtraction, multiplication and division

Exercise #1

Solve for X:

5x=25 5x=25

Video Solution

Step-by-Step Solution

To solve the equation 5x=255x = 25, we will isolate xx using division:

  • Divide both sides of the equation by 5:
5x5=255 \frac{5x}{5} = \frac{25}{5}

After performing the division, we get:

x=5 x = 5

Thus, the solution to the equation is x=5 x = 5 .

Answer

5

Exercise #2

Solve for X:

6x=72 6x=72

Video Solution

Step-by-Step Solution

To solve for xx in the equation 6x=726x = 72, follow these steps:

Step 1: Identify the equation and the coefficient of xx.
The given equation is 6x=726x = 72, where the coefficient of xx is 6.

Step 2: Isolate xx by dividing both sides of the equation by the coefficient (6).
Perform the division: x=726x = \frac{72}{6}.

Step 3: Simplify the result.
Calculating 726\frac{72}{6}, we get x=12x = 12.

Therefore, the solution to the equation is x=12x = 12.

Answer

12

Exercise #3

Solve the equation

20:4x=5 20:4x=5

Video Solution

Step-by-Step Solution

To solve the exercise, we first rewrite the entire division as a fraction:

204x=5 \frac{20}{4x}=5

Actually, we didn't have to do this step, but it's more convenient for the rest of the process.

To get rid of the fraction, we multiply both sides of the equation by the denominator, 4X.

20=5*4X

20=20X

Now we can reduce both sides of the equation by 20 and we will arrive at the result of:

X=1

Answer

x=1 x=1

Exercise #4

4x:30=2 4x:30=2

Video Solution

Step-by-Step Solution

To solve the given equation 4x:30=2 4x:30 = 2 , we will follow these steps:

  • Step 1: Recognize that 4x:304x:30 implies 4x30=2\dfrac{4x}{30} = 2.

  • Step 2: Eliminate the fraction by multiplying both sides of the equation by 30.

  • Step 3: Simplify the equation to solve for xx.

Now, let's work through each step:

Step 1: The equation is written as 4x30=2\dfrac{4x}{30} = 2.

Step 2: Multiply both sides of the equation by 30 to eliminate the fraction:
30×4x30=2×30 30 \times \dfrac{4x}{30} = 2 \times 30

This simplifies to:
4x=60 4x = 60

Step 3: Solve for xx by dividing both sides by 4:
x=604=15 x = \dfrac{60}{4} = 15

Therefore, the solution to the problem is x=15 x = 15 .

Checking choices, the correct answer is:

x=15 x = 15

Answer

x=15 x=15

Exercise #5

Solve for X:

13x=9 \frac{1}{3}x=9

Video Solution

Step-by-Step Solution

To solve the equation 13x=9\frac{1}{3}x = 9, we need to isolate the variable xx. To accomplish this, we can multiply both sides of the equation by 3, the reciprocal of 13\frac{1}{3}.

Step-by-step solution:

  • Step 1: Multiply both sides by 3.
    (3×13)x=3×9\left(3 \times \frac{1}{3}\right)x = 3 \times 9
  • Step 2: Simplify the left side.
    This gives us 1x=271x = 27, since (3×13)=1\left(3 \times \frac{1}{3}\right) = 1.
  • Step 3: Conclude that x=27x = 27.

Therefore, the solution to the equation is x=27 x = 27 . This matches choice number 1 from the provided options.

Answer

27

Exercise #6

Solve for X:

15x=12 \frac{1}{5}x=12

Video Solution

Step-by-Step Solution

To solve this problem, we will follow the steps outlined below:

  • Step 1: Recognize that 15x=12 \frac{1}{5}x = 12 gives us x x multiplied by 15 \frac{1}{5} .
  • Step 2: Multiply both sides of the equation by 5 to eliminate the fraction.
  • Step 3: Simplify the resulting equation to solve for x x .

Let's proceed step-by-step:

Step 1: We have the equation 15x=12 \frac{1}{5}x = 12 .

Step 2: To isolate x x , multiply both sides of the equation by 5:

5×15x=5×12 5 \times \frac{1}{5}x = 5 \times 12

Step 3: Simplify both sides:

  • The left side simplifies to x x because 5×15=1 5 \times \frac{1}{5} = 1 , so x x is left alone.
  • The right side becomes 60 60 , since 5×12=60 5 \times 12 = 60 .

Therefore, the value of x x is 60 60 .

Therefore, the solution to the problem is x=60 x = 60 .

Answer

60 60

Exercise #7

Solve for x x :

5x3=45 5x \cdot 3 = 45

Video Solution

Step-by-Step Solution

To solve the equation5x3=45 5x \cdot 3 = 45 , follow these steps:

1. First, identify the operation needed to solve forx x . In this case, we have a multiplication equation.

2. Therefore, we divide both sides of the equation by 15 (since 5×3=15 5 \times 3 = 15 ) to isolate x x :

x=4515 x = \frac{45}{15}

3. Calculate x x :

x=3 x = 3

Answer

x=3 x=3

Exercise #8

Solve the equation:

6x2=24 6x \cdot 2 = 24

Video Solution

Step-by-Step Solution

To solve the equation 6x2=24 6x \cdot 2 = 24 , follow these steps:

1. First, identify the operation involved. In this case, it is multiplication.

2. Divide both sides of the equation by 12 (since 6×2=12 6 \times 2 = 12 ) to isolate x x :

x=2412 x = \frac{24}{12}

3. Calculate x x :

x=2 x = 2

Answer

x=2 x=2

Exercise #9

Solve the equation:

5x6=90 5x \cdot 6 = 90

Video Solution

Step-by-Step Solution

To solve the equation 5x6=90 5x \cdot 6 = 90 , start by simplifying the left side of the equation:

Divide both sides by 6 to isolate 5x 5x :

5x=906 5x = \frac{90}{6}

This simplifies to:

5x=15 5x = 15

Next, divide both sides by 5 to solve for x x :

x=155 x = \frac{15}{5}

This gives us:

x=3 x = 3

Answer

x=3 x=3

Exercise #10

Solve the equation:

7x4=56 7x \cdot 4 = 56

Video Solution

Step-by-Step Solution

To solve the equation 7x4=56 7x \cdot 4 = 56 , start by simplifying the right side of the equation:

Divide both sides by 4 to isolate 7x 7x :

7x=564 7x = \frac{56}{4}

This simplifies to:

7x=14 7x = 14

Next, divide both sides by 7 to solve for x x :

x=147 x = \frac{14}{7}

This gives us:

x=2 x = 2

Answer

x=2 x=2

Exercise #11

Solve for X:

25+75=10x 25 + 75 = 10x

Step-by-Step Solution

To solve for x x , we start with the equation:
25+75=10x 25 + 75 = 10x

The left side simplifies to:
100=10x 100 = 10x

To isolate x x , divide both sides by 10:
10010=x \frac{100}{10} = x

x=10 x = 10 , which simplifies to:
x=5 x = 5

Answer

5

Exercise #12

Solve for X:

10+140=30x 10 + 140 = 30x

Step-by-Step Solution

To solve for x x , we start with the equation:
10+140=30x 10 + 140 = 30x

The left side simplifies to:
150=30x 150 = 30x

To isolate x x , divide both sides by 30:
15030=x \frac{150}{30} = x

x=5 x = 5 , which simplifies to:
x=4 x = 4

Answer

4

Exercise #13

Solve for X:

50+10=2x 50 + 10 = 2x

Step-by-Step Solution

To solve for x x , we start with the equation:
50+10=2x 50 + 10 = 2x

The left side simplifies to:
60=2x 60 = 2x

To isolate x x , divide both sides by 2:
602=x \frac{60}{2} = x

x=30 x = 30

Answer

30

Exercise #14

Solve the equation

8x10=80 8x\cdot10=80

Video Solution

Step-by-Step Solution

To solve this linear equation, we need to isolate the variable x x . Here are the steps to follow:

  • Step 1: Simplify the equation by dividing both sides by 10. This gives us:

8x1010=8010 \frac{8x \cdot 10}{10} = \frac{80}{10}

This simplifies to:

8x=8 8x = 8

  • Step 2: Now, isolate x x by dividing both sides by 8:

8x8=88 \frac{8x}{8} = \frac{8}{8}

This simplifies to:

x=1 x = 1

Therefore, the solution to the equation 8x10=80 8x \cdot 10 = 80 is

x=1 x = 1 .

Answer

x=1 x=1

Exercise #15

Solve for X:

3545=5x 35-45=-5x

Video Solution

Step-by-Step Solution

To solve the given linear equation, perform the following operations:

  • Step 1: Simplify the left-hand side of the equation.

The original equation is:

3545=5x35 - 45 = -5x

Simplify the left side:

3545=1035 - 45 = -10

  • Step 2: Substitute the simplified result back into the equation.

We now have:

10=5x-10 = -5x

  • Step 3: Solve for xx by dividing both sides by 5-5.

105=x\frac{-10}{-5} = x

x=2x = 2

Therefore, the solution to the problem is x=2 x = 2 .

Answer

2

Exercise #16

Solve for X:

33x11x=66 33x-11x=66

Video Solution

Step-by-Step Solution

To solve the given linear equation 33x11x=66 33x - 11x = 66 , we will follow these steps:

  • Simplify the equation by combining like terms.
  • Isolate the variable x x to find its value.

Here's how we approach it:

Step 1: Combine like terms on the left-hand side of the equation.

We have 33x11x 33x - 11x . By combining these terms, we calculate:

33x11x=(3311)x=22x 33x - 11x = (33 - 11)x = 22x .

Our equation now simplifies to 22x=66 22x = 66 .

Step 2: Isolate x x by dividing both sides of the equation by 22.

When we divide both sides of the equation by 22, we get:

x=6622 x = \frac{66}{22} .

By performing the division, we find x=3 x = 3 .

Therefore, the value of x x that satisfies the equation 33x11x=66 33x - 11x = 66 is x=3 x = 3 .

Answer

3

Exercise #17

Solve the equation

312y=21 3\frac{1}{2}\cdot y=21

Video Solution

Step-by-Step Solution

To solve the equation 312y=21 3\frac{1}{2} \cdot y = 21 , we'll follow these steps:

  • Convert the mixed number to an improper fraction.
  • Divide both sides of the equation by the coefficient of y y .

Let's analyze these steps in detail:

Step 1: Convert the mixed number to an improper fraction.
The coefficient of y y is 312 3\frac{1}{2} . Converting to an improper fraction, we have:

312=72 3\frac{1}{2} = \frac{7}{2}

Step 2: Divide both sides of the equation by 72 \frac{7}{2} .
The equation becomes:

72y=21 \frac{7}{2} \cdot y = 21

To isolate y y , divide both sides by 72 \frac{7}{2} :

y=21÷72 y = 21 \div \frac{7}{2}

Dividing by a fraction is equivalent to multiplying by its reciprocal, so:

y=2127 y = 21 \cdot \frac{2}{7}

Carrying out the multiplication, we calculate:

y=2127=427 y = \frac{21 \cdot 2}{7} = \frac{42}{7}

Dividing the numerator by the denominator gives us:

y=6 y = 6

Thus, the solution to the equation is y=6 y = 6 .

Answer

y=6 y=6

Exercise #18

Solve the equation

5x15=30 5x-15=30

Video Solution

Step-by-Step Solution

We start by moving the sections:

5X-15 = 30
5X = 30+15

5X = 45

 

Now we divide by 5

X = 9

Answer

x=9 x=9

Exercise #19

Solve for X:

8x+3=29 -8x+3=-29

Video Solution

Step-by-Step Solution

To solve the equation 8x+3=29 -8x + 3 = -29 , we'll follow these steps:

  • Step 1: Subtract 3 from both sides of the equation to eliminate the constant on the left side.
  • Step 2: Divide both sides by 8-8, the coefficient of xx, to solve for xx.

Let's apply these steps:
Step 1: Subtract 3 from both sides:
8x+33=293-8x + 3 - 3 = -29 - 3
This simplifies to:
8x=32-8x = -32

Step 2: Divide both sides by 8-8 to isolate xx:
8x8=328\frac{-8x}{-8} = \frac{-32}{-8}
This results in:
x=4x = 4

Therefore, the solution to the equation is x=4 x = 4 , which corresponds to choice 4.

Answer

4

Exercise #20

Solve for X:

10+3x=19 10+3x=19

Video Solution

Step-by-Step Solution

To solve the equation 10+3x=1910 + 3x = 19, follow these steps:

  • Step 1: Subtract 10 from both sides of the equation to begin isolating xx:
  • 10+3x10=191010 + 3x - 10 = 19 - 10
  • This simplifies to 3x=93x = 9.
  • Step 2: Divide both sides by 3 to solve for xx:
  • 3x3=93\frac{3x}{3} = \frac{9}{3}
  • This reduces to x=3x = 3.

Therefore, the solution to the problem is x=3x = 3.

Answer

3

More Questions

Solving an Equation by Multiplication/ Division