Big Ideas Math: Modeling Real Life, Grade 8
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Big Ideas Math: Modeling Real Life, Grade 8 View details
1. Solving Simple Equations
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Exercise 42 Page 10

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

x=- 1 49

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 the Properties of Equality. In this case, the variable term is already on the right-hand side of the equation, so we will start by simplifying the constants in the equation.
8/9=x+1/3(7)
8/9=x+7/3
8/9-7/3=x+7/3-7/3
â–Ľ
Simplify denominator
8/9-7* 3/3* 3=x+7/3-7/3
8/9-21/9=x+7/3-7/3
- 13/9=x
- 1 49=x
x=- 1 49
The solution to the equation is x= - 1 49. We can check our solution by substituting it into the original equation.
8/9=x+1/3(7)
8/9? = - 1 49+1/3(7)
â–Ľ
Simplify
8/9? =- 1* 9+4/9+1/3(7)
8/9? =- 9+4/9+1/3(7)
8/9? =- 13/9+1/3(7)
8/9? =- 13/9+7/3
8/9? =- 13/9+7* 3/3* 3
8/9? =- 13/9+21/9
8/9=8/9 âś“
Since the left-hand side is equal to the right-hand side, our solution is correct.