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Pearson Geometry Common Core, 2011

PG

Pearson Geometry Common Core, 2011 View details

Chapter Review

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Exercise 10 Page 481

You can solve for the variable by using cross products.

7

Practice makes perfect

To solve the proportion, we will start by using cross products. Remember that we will need to treat the expressions x+9 and x-3 as single quantities in the cross multiplication process.

8/x+9=2/x-3

Cross multiply

8(x-3)=(x+9)2

From here, we will continue solving for x by using the Distributive Property and the Properties of Equality.

8(x-3)=(x+9)2

Distribute 8

8x-24=(x+9)2

Distribute 2

8x-24=2x+18

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Solve for x

LHS+24=RHS+24

8x=2x+18+24

LHS-2x=RHS-2x

8x-2x=18+24

Add and subtract terms

6x=42

.LHS /6.=.RHS /6.

x=7