(1)(X^2-Y^2)/(X^2+2XY+Y^2)
=(X+Y)(X-Y)/(X+Y)^2
=(X-Y)/(X+Y)
∵X=100,Y=10
∴(100-10)/(100+10)=9/11
(2)a-b3ab=0你应该少打了一个符号吧
如果是a-b-3ab=0
a-b=3ab
(2a+3ab-2b)/(a-ab-b)
=[2(a-b)+3ab]/[(a-b)-ab]
=9ab/2ab
=9/2
如果是a-b+3ab=0
a-b=-3ab
(2a+3ab-2b)/(a-ab-b)
=[2(a-b)+3ab]/[(a-b)-ab]
=(-3ab)/(-4ab)
=3/4