x/y=-2
则
x=-2y
则
原式
=(x²-2xy-3y²)/(x²-6xy-7y²)
=(x+y)(x-3y)/(x+y)(x-7y)
=(x-3y)/(x-7y)
=(-2y-3y)/(-2y-7y)
=(-5y)/(-9y)
=5/9
若y分之x等于负2,求x的二次方减6xy减7y的二次方分之x的二次方减2xy减3y的二次方的值?
若y分之x等于负2,求x的二次方减6xy减7y的二次方分之x的二次方减2xy减3y的二次方的值?
数学人气:258 ℃时间:2019-10-19 14:59:23
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