\(a,x^2-y^2-2x+2y\\ =\left(x-1\right)^2-\left(y-1\right)^2\\ =\left(x-1-y+1\right)\left(x-1+y-1\right)\\ =\left(x-y\right)\left(x+y-2\right)\\ b,2x+2y-x^2-xy\\ =\left(2-x\right)\left(x+y\right)\\ c,3a^2-6ab+3b^2-12c^2\\ =3\left(a-b\right)^2-12c^2\\ =\left[\sqrt{3}\left(a-b\right)-2\sqrt{3}c\right]\left[\sqrt{3}\left(a-b\right)+2\sqrt{3}c\right]\\ =\left(\sqrt{3}a-\sqrt{3}b-2\sqrt{3}c\right)\left(\sqrt{3}a-\sqrt{3}b+2\sqrt{3}c\right)\\ =3\left(a-b-2c\right)\left(a-b+2c\right)\)
\(d,x^2-25+y^2+2xy\\ =\left(x+y-5\right)\left(x+y+5\right)\\ e,a^2+2ab+b^2-ac-bc\\ =\left(a+b\right)^2-c\left(a+b\right)\\ =\left(a+b-c\right)\left(a+b\right)\\ f,x^2-2x-4y^2-4y\\ =\left(x-1\right)^2-\left(2y+1\right)^2\\ =\left(x-1-2y-1\right)\left(x-1+2y+1\right)\\ =\left(x-2y-2\right)\left(x+2y\right)\\ g,x^2y-x^3-9y-9x\\ =x^2\left(y-x\right)-9\left(y-x\right)\\ =\left(x-3\right)\left(x+3\right)\left(y-x\right)\\ h,x^2\left(x-1\right)+16\left(1-x\right)\\ =\left(x-4\right)\left(x+4\right)\left(x-1\right)\)
a: Ta có: \(x^2-y^2-2x+2y\)
\(=\left(x-y\right)\left(x+y\right)-2\left(x-y\right)\)
\(=\left(x-y\right)\left(x+y-2\right)\)
b: Ta có: \(2x+2y-x^2-xy\)
\(=2\left(x+y\right)-x\left(x+y\right)\)
\(=\left(x+y\right)\left(2-x\right)\)
