Answer:
V = 4x⁴ - 60x³ + 216x²
Step-by-step explanation:
V = length x width x height = l x w x h
let x = side of a cut-out square (all side are of a square are equal)
l = 18-2x
w = 12-2x
h = x
V = (18-2x)(12-2x)(x)
V = (18x - 2x²)(12x - 2x²)
V = 216x² - 36x³ - 24x³ + 4x⁴
V = 4x⁴ - 60x³ + 216x²