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 27 Page 9

Use the Multiplication Property of Equality to eliminate the division.

k=1 23

Practice makes perfect
To solve the equation, we have to isolate k on one side. Using the Multiplication Property of Equality, we will multiply both sides of the equation by 10 and eliminate the denominators of the fractions.
3/2=9/10k
3/2* 10=9/10k* 10
â–Ľ
Simplify left-hand side
3* 10/2=9/10k* 10
30/2=9/10k* 10
15=9/10k* 10
15=9/10* 10k
15=9k
Now, we can use the Division Property of Equality to divide both sides of the equation by 9. This will eliminate the coefficient of k and isolate it on the right-hand side of the equation.
15=9k
15/9=9k/9
5/3=9k/9
â–Ľ
Simplify right-hand side
5/3=k/1
5/3=k
1 23=k
k=1 23
To check that this solution is correct, let's substitute k= 1 23 into the original equation and simplify.
3/2=9/10k
3/2? =9/10( 1 23)
â–Ľ
Simplify right-hand side
3/2? =9/10(1* 3+2/3)
3/2? =9/10(3+2/3)
3/2? =9/10(5/3)
3/2? =9* 5/10* 3
3/2? =45/30
3/2=3/2 âś“
Since the left-hand side and right-hand side are equal, k=1 23 is the correct solution.