Envision Math 2.0: Grade 8, Volume 1
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2. Solve Equations with Variables on Both Sides
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Exercise 7 Page 94

Gather all of the variable terms on one side of the equation and all of the constant terms on the other side.

b=6

Practice makes perfect
To solve an equation, we should first gather all of the variable terms on one side and all of the constant terms on the other side using inverse operations. In this case, we need to start by adding 2.6b to both sides of the equation to isolate the b-terms on the right-hand side.
- 2.6b+4=0.9b-17
- 2.6b+4+ 2.6b=0.9b-17+ 2.6b
- 2.6b+2.6b+4=0.9b+2.6b-17
4=3.5b-17
Now, we will add 17 to both sides of the equation to isolate the constant terms on the left-hand side.
4=3.5b-17
4+ 17=3.5b-17+ 17
21=3.5b
Finally, to solve the equation we should divide both sides by the number standing next to the variable. To avoid division by a decimal, we will first multiply both sides of the equation by 2.
21=3.5b
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Solve for b
21* 2=3.5b* 2
21* 2=3.5* 2* b
42=7b
42 Ă· 7 = 7b Ă· 7
6=b
b=6
The solution to the equation is b=6.