the length of a rectangle is 8 feet more its width. the area of the rectangle is 84 square feet find its length and width

length=8+w ... 1

area=84square feet ... 2

area of rectangle = length x width

area = (8+w) x W

area=8w+w^2

84=8w+w^2

w^2+8w + (4^2) = 84 + (4^2)

(w+4) ^2=84+16

(w+4) ^2=100

√ (w+4) ^2=√100

w+4=±100

w+4=100 or w+4=-100

w=96 or w=-104

the answer is 96