1.原题应为 “若a+1/a=7,则根号a+1/根号a=?即√a+1/√a=?" ∵ (√a+1/√a) =a+2+1/a =2+(a+1/a) =2+7 =9.又√a≥0,1/√a>0 则√a+1/√a>0,∴√a+1/√a=√9=3.2.原题是这样吧：“定义运算 a 的运算法则为x a y=√(xy+...