Find the volume of rectangle.

Question

Solve for N.  Find the volume of rectangle. Length =4 with = (n+2), hight = (n+5). I am not sure how to multiply this to get volume= lwh. Total volume is 280 in^3

Answer 1

V=lwh

280=(4)(n+2)(n+5)

280=(4)(n^2+7n+10)

280/4=n^2+7n+10

70=n^2+7n+10

0=n^2+7n+10-70

0=n^2+7n-60

n^2+7n-60=0

(n+12)(n-5)=0

n+12=0

n=-12 which you do not use

n-5=0

n=5

width=5+2=7 inches

height=5+5=10 inches

check: 280=4*7*10

          280=280