a) (8x6−4x5+12x4−20x3):4x3 = (8x6−4x5+12x4−20x3):4x3=(8x6:4x3)−(4x5:4x3)+(12x4:4x3)−(20x3:4x3)=2x3−x2+3x−5
b)
Vậy (2x2−5x+3):(2x−3) = x - 1