2:
a: =3x^2-3xy-(5x-5y)
=3x(x-y)-5(x-y)
=(x-y)(3x-5)
b: =6x(2x-y)-3y(2x-y)
=(2x-y)(6x-3y)
=3(2x-y)^2
c: =x(a-b)-y(a-b)
=(a-b)(x-y)
d: =x^2(a-b)-y^2(a-b)
=(a-b)(x^2-y^2)
=(x-y)(x+y)(a-b)
e: \(=6y\left(2x^2-3xy-5y^2\right)\)
=6y(2x^2-5xy+2xy-5y^2)
=6y[x(2x-5y)+y(2x-5y)]
=6y(2x-5y)(x+y)
f: =5x(x-y)-10(x-y)
=(x-y)(5x-10)
=5(x-2)(x-y)
g: =3x-4x+3y-4y
=-x+y
h: =7x(x-y)+(x-y)
=(x-y)(7x+1)
k: =(5x)^2-(3x+3y)^2
=(5x-3y-3x)(5x+3x+3y)
=(8x+3y)*(2x-3y)