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1.已知x+4y=-1 xy=5 求(6xy+7y)+[8x-(5xy-y-6x)]的值
额 那么X和Y等于多少的值应该怎么求啊。题目果然打错了
人气:406 ℃ 时间:2020-03-19 20:31:08
解答
题目写错
应该是求(6xy+7y)+[8x-(5xy-y+6x)]
(6xy+7y)+[8x-(5xy-y+6x)]
=6xy+7y+8x-5xy+y-6x
=xy+2x+8y
=xy+2(x+4y)
=5+2×(-1)
=5-2
=3
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