把(x-y),(a+b)作为一个因式,合并同类项.(1)3(x-y)^2-9(x-y)-8(x-y)^2+6(x-y)-1 (2)2(a+b)-5/8(a+b)^2-2/3(a+b)+3(a+b)^2+2

3(x-y)^2-9(x-y)-8(x-y)^2+6(x-y)-1
=-5(x-y)^2-3(x-y)-1
2(a+b)-5/8(a+b)^2-2/3(a+b)+3(a+b)^2+2
=19/8(a+b)^2-4/3(a+b)+3(a+b)^2+2