Respuesta :

(9x-27)x = 972
9x²-27x = 972
9x²-27x-972 = 0
x²-3x-108 = 0
(x+9)(x-12) = 0
x = -9 or x = 12
Because x has to be >0, thus x = 12 therefore the length of the rectangle is 9(12)-27 = 81