#### Answer

$x=-5,5$

#### Work Step by Step

Isolate the variable factor on one side, and then take the $n$th root of both sides to solve for the variable. If the root is even, there will be a positive and negative answer. If the root is odd and the other side is negative, there is only a negative answer.
$3x^4-600=1275$
$3x^4=1875$
$x^4=625$
$x=-5,5$