\(3x^3y-12x^2y^2+6x^2y=3x^2y\left(x-4y+2\right)\)
\(\left(3x-2\right)^2-\left(x+1\right)^2=\left(3x-2-x-1\right)\left(3x-2+x+1\right)=\left(2x-3\right)\left(4x-1\right)\)
\(x^2+9x+14=x^2+2x+7x+14=x\left(x+2\right)+7\left(x+2\right)=\left(x+2\right)\left(x+7\right)\)
\(3x^2-14x+16=3x^2-6x-8x-16=3x\left(x-2\right)-8\left(x-2\right)=\left(3x-8\right)\left(x-2\right)\)
\(x^8+x+1\)
\(=\left(x^8-x^7+x^5-x^4+x^2\right)+\left(x^7-x^6+x^4-x^3+x\right)+x^6-x^5+x^3-x^2+1\)
\(=x^2\left(x^6-x^5+x^3-x^2+1\right)+x\left(x^6-x^5+x^3-x^2+1\right)+x^6-x^5+x^3-x^2+1\)
\(=\left(x^2+x+1\right)\left(x^6-x^5+x^3-x^2+1\right)\)
\(x^3-5x+2\)
\(=x^3+2x^2-x-2x^2-4x+2\)
\(=x\left(x^2+2x-1\right)-2\left(x^2+2x-1\right)\)
\(=\left(x-2\right)\left(x^2+2x-1\right)\)