V = 4(x+1)(x + 11) = 924 → ( divide both sides by 4)
(x + 1)(x + 11) = 231 → ( expand and rearrange )
x² + 12x + 11 - 231 = 0
x² + 12x - 220 = 0 → ( factoring gives )
(x - 10)(x + 22) = 0 → ( equate each factor to zero and solve for x )
x - 10 = 0 ⇒ x = 10
x + 22 = 0 ⇒ x = - 22
but x > 0 ⇒ x = 10
dimensions of cuboid are 4 cm, 11 cm , 21 cm
check → 4 × 11 × 21 = 924 ' the volume of the cuboid '
