Question

5. The length of a rectangle is 5 inches shorter

than its width. If the area is 84in?, find the
length and width.
show your work

Answer 1

I just looked it up and this is what I found:

L=5+W
LW=84
(5+W)W = 84
W^2 + 5W -84 = 0

either factor, complete the square or use the quadratic formula
factoring is trial and error, look for factors of 84: 4,3 and 7

(W+12)(W-7) = 0
W= 7,-12, ignore the negative width
L=7+5 = 12 = length
7 inches by 12 inches

7x12 =84 square inches