#### Answer

$x=\arcsin(4y)$

#### Work Step by Step

The goal is to isolate x.
Multiply with 4 ...
$4y=\sin x$ $\qquad$ ...use the definition of arcsin
$\arcsin 4y=x$
(4y is the number from $[-\displaystyle \frac{\pi}{2}, \displaystyle \frac{\pi}{2}]$ such that $\sin x$=4y)