Examples with solutions for Solving Equations by using Addition/ Subtraction: Solving an equation using all techniques

Exercise #1

Solve the following exercise:

3(4a+8)=27a -3(4a+8)=27a

a=? a=\text{?}

Video Solution

Step-by-Step Solution

To open the parentheses on the left side, we'll use the formula:

a(b+c)=abac -a\left(b+c\right)=-ab-ac

12a24=27a -12a-24=27a

We'll arrange the equation so that the terms with 'a' are on the right side, and maintain the plus and minus signs during the transfer:

24=27a+12a -24=27a+12a

Let's group the terms on the right side:

24=39a -24=39a

Let's divide both sides by 39:

2439=39a39 -\frac{24}{39}=\frac{39a}{39}

2439=a -\frac{24}{39}=a

Note that we can reduce the fraction since both numerator and denominator are divisible by 3:

813=a -\frac{8}{13}=a

Answer

813 -\frac{8}{13}

Exercise #2

a4+7a5=2a+a4+3a(a) a^4+7a-5=2a+a^4+3a-(-a)

a=? a=?

Video Solution

Step-by-Step Solution

First, let's isolate a from the parentheses in the equation on the right side. We'll remember that minus times minus becomes plus, so we get the equation:

a4+7a5=2a+a4+3a+a a^4+7a-5=2a+a^4+3a+a

Let's continue solving the equation on the right side by adding 2a+3a+a=5a+a=6a 2a+3a+a=5a+a=6a

Now the equation we got is:

a4+7a5=6a+a4 a^4+7a-5=6a+a^4

Let's divide both sides by a4 a^4 and we get:

7a5=6a 7a-5=6a

Now let's move 6a to the left side and the number 5 to the right side, remembering to change the plus and minus signs accordingly.

The equation we got now is:

7a6a=5 7a-6a=5

Let's solve the subtraction and we get:

1a=5 1a=5

Let's divide both sides by 1 and we find that a=5 a=5

Answer

5 5

Exercise #3

4(b2+b)13=6b 4(\frac{b}{2}+b)-\frac{1}{3}=6b

b=? b=\text{?}

Video Solution

Step-by-Step Solution

First, we'll open the parentheses by multiplying each term by 4:

4×b2+4×b13=6b 4\times\frac{b}{2}+4\times b-\frac{1}{3}=6b

Let's solve the multiplication exercise 4×b2=4b2=2b 4\times\frac{b}{2}=\frac{4b}{2}=2b

Now the equation is:

2b+4b13=6b 2b+4b-\frac{1}{3}=6b

We'll combine the left side between the two b terms and get:

6b13=6b 6b-\frac{1}{3}=6b

We'll reduce both sides by 6b and get:

13=0 -\frac{1}{3}=0

Since the result obtained is impossible, the exercise has no solution.

Answer

No solution

Exercise #4

Solve for X:

3(x4)+8x=14 3-(x-4)+8x=14

Video Solution

Answer

1 1

Exercise #5

Solve for X:

8+2(x+1)=7x 8+2(x+1)=7x

Video Solution

Answer

2 2

Exercise #6

37b+6b+56=90+9 37b+6b+56=90+9

b=? b=\text{?}

Video Solution

Answer

1

Exercise #7

4y7+6y=310y 4y-7+6y=3-10y

y=? y=?

Video Solution

Answer

12 \frac{1}{2}

Exercise #8

6c+7+4c=3(c1) 6c+7+4c=3(c-1)

c=? c=\text{?}

Video Solution

Answer

137 -1\frac{3}{7}

Exercise #9

7y+10y+5=2(y+3) 7y+10y+5=2(y+3)

y=? y=\text{?}

Video Solution

Answer

115 \frac{1}{15}

Exercise #10

14a+5=20+a \frac{1}{4}a+5=20+a

a=? a=\text{?}

Video Solution

Answer

20 -20

Exercise #11

Solve for X:

(32x)5=4+12x (3-2x)\cdot5=4+12x

Video Solution

Answer

12 \frac{1}{2}

Exercise #12

Solve for X:

6(5+2x)=3x6 6\cdot(5+2x)=3x-6

Video Solution

Answer

4 -4

Exercise #13

12y+3y10+7(y4)=2y 12y+3y-10+7(y-4)=2y

y=? y=?

Video Solution

Answer

1.9 1.9

Exercise #14

16a20a+15=2(52a) 16a-20a+15=2(5-2a)

a=? a=\text{?}

Video Solution

Answer

No solution

Exercise #15

3x+23=4(x+112) 3x+\frac{2}{3}=4(x+\frac{1}{12})

x=? x=\text{?}

Video Solution

Answer

13 \frac{1}{3}

Exercise #16

13(x+9)=4+23x \frac{1}{3}(x+9)=4+\frac{2}{3}x

x=? x=\text{?}

Video Solution

Answer

3-

Exercise #17

Solve for X:

12(8x)+12x=12x \frac{1}{2}\cdot(8-x)+\frac{1}{2}x=12-x

Video Solution

Answer

8 8

Exercise #18

Solve for X:

14(x16)+34x=8x11 \frac{1}{4}(x-16)+\frac{3}{4}x=8x-11

Video Solution

Answer

1 1

Exercise #19

2x+4513x=5(x+7) 2x+45-\frac{1}{3}x=5(x+7)

x=? x=\text{?}

Video Solution

Answer

3

Exercise #20

74(x)+2x5(x+3)=x -\frac{7}{4}(-x)+2x-5(x+3)=-x

x=? x=\text{?}

Video Solution

Answer

60 -60