Giải thích các bước giải:
a, x^2(y+1)+ 3(y^2+ 2y+1)= x^2(y+1)+ 3(y+1)^2
=(y+1)(x^2+ 3)
b,10x^2(x+y)- 5y^2(2x+2y)=10x^2(x+y)- 5y^2.2(x+y)
=10(x+y)(x^2-y^2)
=10(x+y)(x+y)(x-y)
=10(x+y)^2(x-y)
c, (x-3)^2- (2-3x)^2= (x-3-2+3x)(x-3+2-3x)
= (4x-5)(5-3x)
d, (x+1)^3+ (x-2)^3= (x+1+x-2)[(x+1)^2-(x+1)(x-2)+ (x-2)^2]
=2x(x^2+ 2x+1- x^2+ 2x-x+ 2+ x^2-4x+4)
=2x(x^2-x+6)
e, x^2+ 2xy+ y^2-4= (x+y)^2-2^2
=(x+y-2)(x+y+2)