a) \(x^2-xy+x=x\left(x-y+1\right)\)
b) \(x\left(x-y\right)-2\left(y-x\right)\)
=\(x\left(x-y\right)+2\left(x-y\right)\)
=\(\left(x+2\right)\left(x-y\right)\)
c) \(9x^2-4y^2=\left(3x\right)^2-\left(2y\right)^2=\left(3x-2y\right)\left(3x+2y\right)\)
d) \(x^2-xy-4x+2y+4\)
= \(\left(x^2-4x+4\right)+\left(2y-xy\right)\)
= \(\left(x-2\right)^2-y\left(x-2\right)\)
= \(\left(x-2\right)\left(x-2-y\right)\)
Chuc ban hoc tot !!!