a) (x-2)² = x² - 4x + 4
b) (3y+2)³ = 27y³ + 54y² + 36y + 8
c) (4a-3)(4a+3) = 16a² - 9
d) (x+5)(2x-4) = 2x² - 4x + 10x - 20
=> (x+5)(2x-4) = 2x² + 6x - 20
