设y=y(x)是由方程所确定的隐函数，则 .=
Themanageriscallingona______customertryingtotalkhimintosigningthecontract．
Afterhisuncledied，theyoungman_____thebeautifulestatewithwhichhechangedfromapoormantoawealthynoble．
求二元函数f(x,y)=x3+8y3-xy的极值。
Onlywhenyouhaveobtainedsufficientdata________cometoasoundconclusion.
