A rectangle has a length of 21 meters less than 7 times its width. If the area of the rectangle is 910 square meters, find the length of the rectangle.

Question

find the length

Answer 1

Let x = width of rectangle in meters

7x - 21 = length rectangle in meters

area = width x length

x(7x - 21) = 910

7x^2 - 21x = 910

7x^2 - 21x - 910 = o

x^2 - 3x - 130 = 0

(x - 13)(x + 10) = 0

x = 13 (reject x = -10)

The width of the rectangle is 13 meters.

The length of the rectangle is 70 meters.