Question 854135

105 = (x+2)(x)(3)

105 = (3x)(x+2)

105 = 3x^2 + 6x

3x^2 + 6x - 105 = 0

x^2 + 2x - 35 = 0

(x-5)(x+7) = 0

x-5 = 0

x = 5

Reject x = -7 because we are dealing with measurement. 

So, the width 5, the length is 7.

THE PROVE

105 = 7x5x3

105 = 35x3

105 = 105