Answer
$3\sqrt[4]{t}$
Work Step by Step
By combining like radicals, the given expression, $
4\sqrt[4]{t}-\sqrt[4]{t}
,$ simplifies to
\begin{array}{l}\require{cancel}
(4-1)\sqrt[4]{t}
\\\\=
3\sqrt[4]{t}
.\end{array}
* Note that it is assumed that all variables represent positive numbers.