z4x6y3的精選

問題詳情：.已知實數x,y滿足則z=4x+6y+3的取值範圍為()A.[17,48]                 B.[17,49]           C.[19,48]           D.[19,49]【回答】B解析由z=4x+6y+3得y=-x+,作出...