Х4-3х3-2х2+13х-21 :х-3
Х⁴-3х³-2х²+13х-21l :х-3 - ---------- x⁴-3x³ x³-2x+7 --------- -2x²+13x - -2x²+6x --------------- 7x-21 - 7x-21 -------- 0 х⁴-3х³-2х²+13х-21l :х-3 =x³-2x+7