Question

合并同类项 求下列各式的值 1.3a+b-(b-a)^2+a-5b+2(a-b)^2,其中a-b=-22.2(x+y)-

Answer 1

(1)a-b=-2

3a+b-(b-a)^2+a-5b+2(a-b)^2

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

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

=-8+4

=-4

(2)

2(x+y)-2/3(x-y）+1/4(x+y)+2/3(x-y)+2/3(x-y)

=9/4(x+y)+2/3(x-y)

=35/12x+19/12y

=-35/24-57/24

=-23/6