A=(x²-3x)(x²-3x+4)+4=x⁴-3x³+4x²-3x³+9x²-12x+4=x⁴-6x³+13x²-12x+4
x⁴-6x³+13x²-12x+4 x-1
-x⁴+x³ x³-5x²+8x-4
= -5x³+13x²-12x+4
5x³-5x²
= 8x²-12x+4
-8x²+8x
= -4x+4
4x-4
==
x³-5x²+8x-4 x-1
-x³+x² x²-4x+4
= -4x²+8x-4
4x²-4x
= 4x-4
-4x+4
= =
A=(x-1)(x-1)(x²-4x+4)=(x-1)(x-1)(x-2)(x-2)=(x-1)²(x-2)²
x₁=x₂=1
x₃=x₄=2