(1).(x+y)(a+2b)
=ax+2bx+ay+2by
(2).(2a+3)(2/3b+5)
=4/3ab+10a+2b+15
(3).(2x+3)(-x-1)
=-2x^2-2x-3x-3
=-2x^2-5x-3
(4).(-2m-1)(3m-2)
=-6m^2+4m-3m+2
=-6m^2+m+2
(5).(x-y)^2
=x^2-2xy+y^2
(6).(-2x+3)^2
=4x^2-12x+9