1/2(A²-B)+1/3(A-B²)+1/6(A²+B²)等于多少?

问题描述:

1/2(A²-B)+1/3(A-B²)+1/6(A²+B²)等于多少?

=(1/2+1/3+1/6)A^2+(-1/2-1/3+1/6)B^2
=A^2-2/3B^2