Evaluate the function at the given values of the independent variables. Simplify the results.

$(x,y,z)=\sqrt[\phantom{2}]{xyz}$

$($a$)(4,4,8)$

$($b$)(0,6,-2)$

$($c$)(8,-7,2)$

$(d),(0,1,-1)$

$[-/4$ Points$]$

Evaluate the function at the given values of the independent variables. Simplify the results.

$(x,y)={\displaystyle \underset{x}{\overset{y}{}}}(2t-3)dt$