Question

The volume of a rectangular box is (x3 - 7x2 - 9x + 63) cubic units. Determine the dimensions of the rectangular box by factoring the volume expression completely.

Answer 1

x3 - 7x2 - 9x + 63
= x2(x - 7) - 9(x - 7)
= (x2 - 9)(x - 7)
= (x - 3)(x + 3)(x-7)

Therefore the dimensions are: 3 cm x 3 cm x 7 cm