Bài làm:
a) \(x^2-2xy+y^2-zx+yz\)
\(=\left(x-y\right)^2-z\left(x-y\right)\)
\(\left(x-y\right)\left(x-y-z\right)\)
a/ \(x^2-2xy+y^2-zx+yz.\)
\(=\left(x-y\right)^2-z\left(x-y\right)\)
\(=\left(x-y\right)\left(x-y-z\right)\)
c/ \(x^2-y^2-2x-2y.\)
\(=x^2-2x+1-y^2-2y-1\)
\(=\left(x^2-2x+1\right)-\left(y^2+2y+1\right)\)
\(=\left(x-1\right)^2-\left(y+1\right)^2\)
\(=\left(x-1+y+1\right)\left(x-1-y-1\right)\)
\(=\left(x+y\right)\left(x-y-2\right)\)
sử dụng hằng thành thạo = ez
\(a,x^2-2xy+y^2-zx+yz\)
\(=\left(x-y\right)\left(x-y\right)-z\left(x-y\right)=\left(x-y\right)\left(x-y-z\right)\)
\(b,a^3-3a+3b-b^3=\left(a^3-b^3\right)-3\left(a-b\right)\)
\(=\left(a-b\right)\left(a^2+ab+b^2\right)-3\left(a-b\right)\)
\(=\left(a-b\right)\left(a^2+ab-b^2-3\right)\)
\(c,x^2-y^2-2x-2y=\left(x-y\right)\left(x+y\right)-2\left(x+y\right)=\left(x+y\right)\left(x-y-2\right)\)
b) \(a^3-3a+3b-b^3\)
\(=\left(a-b\right)\left(a^2+ab+b^2\right)-3\left(a-b\right)\)
\(=\left(a-b\right)\left(a^2+ab+b^2-3\right)\)
c) \(x^2-y^2-2x-2y\)
\(=\left(x-y\right)\left(x+y\right)-2\left(x+y\right)\)
\(=\left(x+y\right)\left(x-y-2\right)\)