Answer:
(x-1)(x-3)(x+1)(x+2)
Step-by-step explanation:
x⁴-x³-7x²+x+6=
x⁴-x³-x²+x -6x²+6=
x³(x-1)-x(x-1)-6(x²-1)=
x³(x-1)-x(x-1)-6(x-1)(x+1)=
(x-1)(x³-x-6x-6)=
(x-1)(x³-3x²+3x²-9x+2x-6)=
(x-1)(x-3)(x²+3x+2)=
(x-1)(x-3)(x²+x+2x+2)=
(x-1)(x-3)(x+1)(x+2)
