Multiply:
(2x2 – 1) × (4x3 + 5x2)
= 2x2 (4x3 + 5x) – 1 (4x3 + 5x2)
= 8x5 + 10x3 – 4x3 – 5x2
= 8x5 + 6x3 – 5x2
