Question

The width of a rectangle is the sum of the length and 5. The area of the rectangle is 36 units. What id the width, in units, of the rectangle?

Answer 1

Explanation:

Let length = x

Width = x + 5

Area = 36

Area = length × width

36 = x(x + 5)

36 = x^2 + 5x

x^2 + 5x - 36 = 0

x^2 + 9x - 4x -36 =0

(x^2 + 9x) - (4x + 36) = 0

x(x + 9) - 4(x + 9) = 0

(x -4)(x+9) = 0

x - 4 = 0 or x + 9 = 0

x = 4 or -9

But x can only be positive because it is a length

x = 4unit = length

Width = x + 5 = 4 +5 = 9unit