Bài 1 :
a,\(x\left(x+y\right)-6x-6y=x\left(x+y\right)-6\left(x+y\right)=\left(x+y\right)\left(x-6\right)\)
b, \(x^3-x-y^2-y??????????\)
c, \(2x^3+16=2\left(x^3+8\right)=2\left(x+3\right)\left(x^2-3x+9\right)\)
d, \(x^4+2x^3+x^2=x^2\left(x^2+2x+1\right)=x^2\left(x+1\right)^2\)
e, \(5x^2-10xy+5y^2-20z^2=5[\left(x-y\right)^2-\left(2z\right)^2]\)
\(=5\left(x-y-2z\right)\left(x-y+2z\right)\)
f, \(16-x^2+2xy-y^2=16-\left(x-y\right)^2=\left(4-x+y\right)\left(4+x-y\right)\)
g, Tương tự e
Bài 2 :
a,\(x^2-10x=-25< =>\left(x-5\right)^2=0< =>x=5\)
b,\(x^2\left(x-2\right)+x-2=0\)
\(\Leftrightarrow\left(x-2\right)\left(x^2+1\right)=0\)
\(x^2+1>0< =>x-2=0< =>x=2\)
c, \(\left(x-2\right)^2=\left(3x-5\right)^2\)
\(< =>\left[{}\begin{matrix}x-2=3x-5\\x-2=5x-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1,5\\x=0,25\end{matrix}\right.\)