1.
x³-5x²-9x+15=
x²(x-5) - 3(x+5)=
(x²-3)(x-5)(x+5)
x²-3=0 x-5=0 x+5=0
x²=3
odp.
x=√3 v x=5 v x=-5
2.
x⁴-81=0
x⁴=81
x=⁴√81
odp.
x=3
3.
6x³+48 /:6
x³=8
odp.
x=2
4.
x³+4x²-x-4 =
x²(x+4)-(x-4) =
(x²-1)(x+4)(x-4)
x²-1=0 x+4=0 x-4=0
x²=1
odp.
x=1 v x=-4 v x=4
