Question

Question 11 options:

The area of a rectangle is 80 cm2.

The length is x – 8, and the width is x + 8.

Find the value of x, and the dimensions of the rectangle.
A = lw

Answer 1

x = 12

length = 4 cm

width = 20 cm

Explanation:

a = lw

Plug in the givens

80 = (x - 8)(x + 8)

Multiply

80 = x^2 - 64

Add 64 to both sides

144 = x^2

Take the square root of both sides

x = ±12

(The negative root is extraneous since the dimensions can not be negative)

x = 12

length = x - 8 = 4 cm

width = x + 8 = 20 cm