Page 587 - Basic College Mathematics with Early Integers

564 C HAPTE R 8 I INTRODUCTION TO ALGEBRA

PRACTICE 16 Example 16 Simplify: -21x - 52 + 412x + 22
Simplify:
Solution: First we use the distributive property to remove parentheses.
-71x - 12 + 512x + 32

–2(x-5)+4(2x+2)=–2(x)-(–2)(5)+4(2x)+4(2) Apply the distributive
property.
=-2x + 10 + 8x + 8 Multiply.
= 6x + 18 Combine like terms.
Work Practice 16

Objective Finding Perimeter and Area

PRACTICE 17 Example 17 Find the perimeter of the triangle.

Find the perimeter of the square.
2z feet 3z feet
2x
centimeters 5z feet
Solution: Recall that the perimeter of a figure is the distance around the figure.
To find the perimeter, then, we find the sum of the lengths of the sides. We use the
letter P to represent perimeter.
P = 2z + 3z + 5z
= 10z Don’t forget to
T insert proper units.
The perimeter is 10z feet.
Work Practice 17

PRACTICE 18 Example 18 Finding the Area of a Basketball Court
Find the area of the rectangular
garden. Find the area of this YMCA basketball court.

(2x 6) ft
(12y 9) yards
3 yards
45 ft
#
Solution: Recall how to find the area of a rectangle. Area = Length Width , or if
A represents area, l represents length, and represents width, we have A = l ww # .
#
A = l w
=45(2x-6) Let l = 45 and w = (2x - 6) .
= 90x - 270 Multiply.
The area is (90x - 270) square feet.
Work Practice 18
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Don’t forget...

Area: Perimeter:
Answers • surface enclosed • distance around
16. 3x + 22 17. 8x cm • measured in square units • measured in units
18. (36y + 27) sq yd