(X/2+Y/3)(Y/3-X/2)+X/2(X/2-Y/3)
=(Y/3)²-(X/2)²+X²/4-XY/6
=Y²/9-X²/4+X²/4-XY/6
=Y²/9-XY/6
代入X=4,Y=6
原式=6²/9-(4×6)/6
=4-6
=-2
这个应该是初一刚学平方差公式的题目吧?
如果是初二的题目:
原式=(X/2+Y/3)(Y/3-X/2)-X/2(Y/3-X/2)
=(Y/3-X/2)(X/2+Y/3-X/2)
=Y/3(Y/3-X/2)
=9Y²-XY/6
然后再代入
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