width of a rectangle

Question

the sum of a rectangle is 7 feet less than its length If the area of the rectangle is 170 square feet then find the width

Answer 1

length=L

width=L-7

A=LxW

A=L(L-7)

170=L(L-7)

170=L²-7L

L²-7L-170=0

(L-17)(L+10)=0

L-17=0

L=17 feet

width=17-7

width=10 feet