Big Ideas Math: Modeling Real Life, Grade 7
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Big Ideas Math: Modeling Real Life, Grade 7 View details
Chapter Review
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Exercise 17 Page 173

y=- 5

Practice makes perfect

To solve the equation, we have to isolate y on one side. Using the Division Property of Equality, we will divide both sides of the equation by 2. This will eliminate the multiplication and isolate y.

- 10=2y
- 10/2=2y/2
2y/2=- 10/2
â–¼
Simplify
2/2y=- 10/2
1y=- 10/2
y=- 10/2
y=-10/2
y=- 5

To check that this solution is correct, let's substitute y=- 5 into the original equation and simplify.

- 10=2y
- 10 ? = 2( - 5)
- 10 ? = - 2(5)
- 10=- 10 ✓

Since the left-hand side and right-hand side are equal, y=- 5 is the correct solution.

Extra

Properties of Equality
There are four main Properties of Equality that we use when solving linear equations.

Properties of Equality
Addition Property of Equality If a=b, then a+c=b+c.
Subtraction Property of Equality If a=b, then a-c=b-c.
Multiplication Property of Equality If a=b, then ac=bc.
Division Property of Equality If a=b and c is not 0, then a/c=b/c.

In later chapters, you will learn about some more advanced Properties of Equality. As an example, there is a property for when we need to eliminate a radical or an exponent.

Power Property of Equality

If a=b, then a^m=b^m.