1)2a(x+y)+x+y
2)3b(x-y)+x-y
3)4a(m-n)+m-n

1) 2a(x+y)+x+y= 2ax+2ay+x+y=(2ax+x)+(2ay+y)=x(2a+1)+y(2a+1)=(x+y)(2a+1)
2) 3b(x-y)+x-y=3bx-3by+x-y=(3bx+x)-(3by+y)=x(3b+1)-y(3b+1)=(x-y)(3b+1)
3) 4a(m-n)+m-n=4am-4an+m-n=(4am+m)-(4an+n)=m(4a+1)-n(4a+1)=(m-n)(4a+1)