=x(x^2-2xy+y^2)-y(y^2-2xy+x^2)

=x^3-2x^2y+xy^2+xy^2-y^3+2xy^2-x^2y

=x^3-y^3+3xy^2-3x^2y

=(x-y)(x^2+xy+y^2)+3xy(y-x)

=(x-y)(x^2-2xy+y^2)

=(x-y)^3

5.m(a^2+b^2)+n(a^2+b^2)

=(m+n)(a^2+b^2)

6. 18(a-b)^3- 12b(b-a)^3

=(a-b)^3( 18+ 12b)

7.(2a+b)(2a-3b)-3a(2a+b)

=(2a+b)(-a-3b)

8.x(x+y)(x-y)-x(x+y)^2

=x(x+y)(x-y-x-y)

=-2xy(x+y)

1.4 times (m-2)-3 times (m-2)

=x(m-2)

= 1.5(6-2)

=6

2.(a-b)^2-6(2-a)

=a^2-2a+b^2- 12+6a

=a^2+4a+b^2- 12

=(a+2)^2+b^2- 16

=(a+2)^2+(b-4)(b+4)

=(b-4)(b+4)

3.(a+b)^2+a(a+b)+(a+b)b

=(a+b)(a+b+a+b)

=2(a+b)^2