5/12[-3/4(x-y)^3]*(x+y)^2*(-x-y)^3*5/6(y-x)^2

问题描述:

5/12[-3/4(x-y)^3]*(x+y)^2*(-x-y)^3*5/6(y-x)^2

原式=4a(a+1)/a(a+2)-a(a-4)/(a+2)2
=4(a+1)/(a+2)-a(a-4)/(a+2)2
=(4a+4)(a+2)-a(a-4)]/(a+2)2
=(3a2+16a+8)/(a+2)2