已知:|x+4y+1|+(xy-5)²=0 求代数式﹙6xy+7y﹚﹢[8x﹣﹙5xy-y+6x﹚]的值
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已知:|x+4y+1|+(xy-5)²=0 求代数式﹙6xy+7y﹚﹢[8x﹣﹙5xy-y+6x﹚]的值
已知:|x+4y+1|+(xy-5)²=0 求代数式﹙6xy+7y﹚﹢[8x﹣﹙5xy-y+6x﹚]的值
已知:|x+4y+1|+(xy-5)²=0 求代数式﹙6xy+7y﹚﹢[8x﹣﹙5xy-y+6x﹚]的值
∵:|x+4y+1|+(xy-5)²=0
∴x+4y+1=0
xy-5=0
∴x+4y=-1
xy=5
﹙6xy+7y﹚﹢[8x﹣﹙5xy-y+6x﹚]
=6xy+7y+8x-5xy+y-6x
=xy+2(x+4y)
=5-2
=3
|x+4y+1|+(xy-5)²=0,所以x+4y=-1,xy=5
﹙6xy+7y﹚﹢[8x﹣﹙5xy-y+6x﹚]=xy+2x+8y=5-2=3