Question

The length of a rectangle is 3 units more than the width. The area of the rectangle is

40 units. What is the length, in units, of the rectangle?

Answer 1

The asnwer is 8 units for the length

Answer 2

8 units for the length

Explanation:

Let l = length

w = width

l = w+3

A = l*w

substitute what we know

40 = (w+3) *w

distribute

40 = w^2 +3w

Subtract 40 from each side

0 = w^2 +3w -40

Factor

0 = (w+8) (w-5)

Using the zero product property

w+8 =0 w-5=0

w= -8 w=5

Since the width cannot be negative

w=5

l = w+3 = 5+3

l = 8 units