\(x^4-6x^3+12x^2-14x+3\)
\(=x^4-2x^3+3x^2-4x^3+8x^2-12x+x^2-2x+3\)
\(=\left(x^4-4x^3+x^2\right)-\left(2x^3-8x^2+2x\right)\)\(+\left(3x^2-12x+3\right)\)
\(=x^2\left(x^2-4x+1\right)-2x\left(x^2-2x+3\right)+3\left(x^2-4x+1\right)\)
\(=\left(x^2-4x+1\right)\left(x^2-2x+3\right)\)
=x4−2x3+3x2−4x3+8x2−12x+x2−2x+3=x4−2x3+3x2−4x3+8x2−12x+x2−2x+3
=(x4−4x3+x2)−(2x3−8x2+2x)=(x4−4x3+x2)−(2x3−8x2+2x)+(3x2−12x+3)+(3x2−12x+3)
=x2(x2−4x+1)−2x(x2−2x+3)+3(x2−4x+1)=x2(x2−4x+1)−2x(x2−2x+3)+3(x2−4x+1)
=(x2−4x+1)(x2−2x+3)