\(\left(x^2+x-1\right)^2+4x^2+4x-1\)
\(=\left(x^2+x-1\right)^2+4\left(x^2+x-1\right)+3\)
\(=\left(x^2+x-1\right)^2+x^2+x-1+3\left(x^2+x-1\right)+3\)
\(=\left(x^2+x-1\right)\left(x^2+x-1+1\right)+3\left(x^2+x-1+1\right)\)
\(=\left(x^2+x-1\right)\left(x^2+x\right)+3\left(x^2+x\right)\)
\(=\left(x^2+x\right)\left(x^2+x-1+3\right)\)
\(=x\left(x+1\right)\left(x^2+x+2\right)\)
Chúc bạn học tốt.