20) If the area of a rectangular playground is p^2 -6p - 7 square feet, what is the perimeter of the
playground?

Explanation:

Write an equation to solve the problem.

Area of rectangle = L(w)

Assuming that the width measures x meters, the length measures x + 5 meters.

500 = x(x + 5)

500 =

x

2

+ 5x

0 =

x

2

+ 5x - 500

As you may already know, a trinomial of the form

a

x

2

+ bx + c, a = 1, you must find 2 numbers that multiply to c and that add to b. Two numbers that multiply to -500 and add to +5 are +25 and -20

0 = (x + 25)(x - 20)

x = -25 and 20

Since a negative length is impossible, the width mesures 20 meters and the length measures 25 meters.

Practice exercises:

A rectangle has a perimeter of 90 meters. Find the maximum area.

The area of a right triangle is 120

m

2

. The base measures half the sum of the height and one. Find the perimeter.

Find the area and perimeter of a right triangle the has a height that is 2 more than the double of the width and that has a hypotenuse that measures

√

68

meters.

Good luck!

Step-by-step explanation: