(x⁴-2x³-2x²+6x-5): (x+1)= x³-3x²+x+5
-x⁴-x³
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= -3x³-2x²+6x-5
3x³+3x²
---------
= x²+6x-5
-x²-x
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= 5x-5
-5x+5
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=
x⁴-2x³-2x²+6x-5=(x+1)(x³-3x²+x+5)
(x²+9)(x²-2x)(x²+2x+1)=0
x²+9=0 x²-2x=0 x²+2x+1=0
brak x(x-2)=0 Δ=2²-4*1*1=4-4=0
pierw. x=0 x=2 x₀=-2/2=-1
x∈{-1,0,2}