A+B
=a^2-2ab+b^2+a^2+2ab+b^2
=2a²+2b²
1/4(B-A)
=1/4【a^2+2ab+b^2-(a^2-2ab+b^2)】
=1/4×4ab
=ab
2A-3B+C=0
那么c=3B-2A
=3(a^2-2ab+b^2)-2(a^2+2ab+b^2)
=a²-10ab+b²
A+B
=a^2-2ab+b^2+a^2+2ab+b^2
=2a²+2b²
1/4(B-A)
=1/4【a^2+2ab+b^2-(a^2-2ab+b^2)】
=1/4×4ab
=ab
2A-3B+C=0
那么c=3B-2A
=3(a^2-2ab+b^2)-2(a^2+2ab+b^2)
=a²-10ab+b²