a) \(A=x^4-6x^3+11x^2-6x+1\)
\(A=\left(x^4-3x^3+x^2\right)-\left(3x^3-9x^2+3x\right)+x^2-3x+1\)
\(A=x^2\left(x^2-3x+1\right)-3x\left(x^2-3x+1\right)+\left(x^2-3x+1\right)\)
\(A=\left(x^2-3x+1\right)^2\)
b) \(B=x^4-x^3+2x^2-11x-5\)
\(B=x^2\left(x^2-2x-1\right)+x\left(x^2-2x-1\right)+5\left(x^2-2x-1\right)\)
\(B=\left(x^2-2x-1\right)\left(x^2+x+5\right)\)