先化简再求值,(3x2平方y-2xy)-2(3xy-x2的平方y) 其中x=负1,y=2 要步骤

2024-12-30 09:28:53
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回答1:

(3x2平方y-2xy)-2(3xy-x2的平方y)
=3x²y-2xy-6xy+2x²y
=5x²y-8xy
=5×1×2+8×2
=10+16
=26