Answer
$x\geq{\frac{13}{4}}$
Work Step by Step
$4x-13$ must be greater than or equal to 0 because a negative number does not have a square root.
$4x-13\geq0$
Simplify to get $4x\geq13$
Divide 4 from both sides to get:
$x\geq{\frac{13}{4}}$