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已知实数x,y满足,若z=y-ax取得最大值时的最优解(x,y)有无数个,则a的...
已知实数x,y满足
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,若z=y-ax取得最大值时的最优解(x,y)有无数个,则a的值为( )
A.-1
B.0
C.1
D.2
考点分析:
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