Pre-Algebra Demystified

SOLUTION

5 ð2xþ3yÞ¼ 5 2xþ 5 3y ¼10xþ15y

EXAMPLE

Multiply 8(xþ3y).

SOLUTION

8 ðxþ3yÞ¼ 8 1xþ 8 3y ¼8xþ24y

The distributive property also works for subtraction.

EXAMPLE
Multiply 9(2x4y).

SOLUTION

9 ð2x4yÞ¼ 9 2x 9 4y
¼18x36y
The distributive property works for the sum or difference of three or more
expressions in parentheses.

EXAMPLE
Multiply 3(6aþ2b7c).

SOLUTION

3 ð6aþ2b7cÞ¼ 3 6aþ 3 2b 3 7c ¼18aþ6b21c

When a negative number is multiplied, make sure to change the signs of
the terms inside the parentheses when multiplying.

EXAMPLE
Multiply2(6p7q3r).

SOLUTION

2 ð6p7q3rÞ¼ 2 6p 2 ð7qÞ 2 ð3rÞ ¼12pþ14qþ6r

CHAPTER 7 Expression and Equations 129