Answer:
l = 7 in; w = 3 in
Step-by-step explanation:
The formula for the area of a rectangle is
A = lw
Data:
A = 21 in²
l = w + 4
Calculation:
21 = (w + 4) × w
21 = w² + 4w
w² + 4w - 21 = 0
(w + 7)(w - 3) = 0
w + 7 = 0 w - 3 = 0
w = -7 w = 3
We reject the negative value, so w = 3 in.
21 = l × 3
l = 7
The rectangle is 7 in long and 3 in wide.
