Width of the rectangle is 5 units
Step-by-step explanation:
Area of the rectangle = length × width
⇒ 40 = x (x - 3)
⇒ 40 = x² - 3x
⇒ x² - 3x - 40 = 0
⇒ x² + 5x - 8x - 40 = 0 (Using Product Sum rule to factorize)
⇒ x(x + 5) - 8(x + 5) = 0
⇒ (x + 5)(x - 8) = 0
⇒ x = -5, 8 (negative value is neglected)
x = 8 and x - 3 = 5