1)
\(6x^2+12xy+6y^2\)
\(=6(x^2+2xy+y^2)=6[(x^2+xy)+(xy+y^2)]\)
\(=6[x(x+y)+y(x+y)]=6(x+y)^2\)
2)
\(-3x^4y^2-6x^3y^2-3x^2y^3\)
\(=-3x^2y^2(x^2+2x+y)\)
3) \(-3x^4y-12x^2y-12x^2y\)
\(=-3x^4y-24x^2y\)
\(=-3x^2y(x^2+8)\)
4)
\(5x^4y^2+20x^3y^2+20x^2y^2\)
\(=5x^2y^2(x^2+4x+4)\)
\(=5x^2y^2[x^2+2x+2x+4]\)
\(=5x^2y^2[x(x+2)+2(x+2)]=5x^2y^2(x+2)^2\)
5)
\(4x^5y^2-8x^4y^2+4x^3y^2\)
\(=4x^3y^2(x^2-2x+1)\)
\(=4x^3y^2(x^2-x-x+1)\)
\(=4x^3y^2[x(x-1)-(x-1)]=4x^3y^2(x-1)^2\)