Answer
{30}
Work Step by Step
For all positive numbers $a$, where $a\ne1$, and all positive numbers $x$, we know that $y=log_{a}x$ means the same as $x=a^{y}$.
Therefore, $log_{4}(2x+4)=3$ means the same as $4^{3}=2x+4$.
We know that $4^{3}=64$, so we can set $64=2x+4$.
Subtract 4 from both sides.
$2x=60$
Divide both sides by 2.
$x=30$