Bài 1:
a,x(x-2)-x^2+3x=x^2-2x-x^2+3x=x
b, (2x-1)^2-(x+1)^2=(2x-1-x-1)(2x-1+x+1)=3x(x-2)=3x^2-6x
Bài 2:
a, x^2y-xy^2-7x+7y=xy(x-y)-7(x-y)=(x-y)(xy-7)
b, 16y^2-x^2+4x-4=16y^2-(x^2-4x+4)\\=16y^2-(x-2)^2=(4y-x+2)(4y+x-2)
Bài 3:
3x^3-75x=0\\\Leftrightarrow 3x(x^2-25)=0\\\Leftrightarrow...