Answer
$$ y =\left(\frac{8t+c}{2}\right)^2.$$
Work Step by Step
We have
$$\frac{dy}{dt}=8\sqrt{y}\Longrightarrow y^{-1/2}dy=8dt\\
\Longrightarrow\int y^{-1/2}dy=8\int dt+c\\
\Longrightarrow 2y^{1/2}=8t+c
\Longrightarrow y =\left(\frac{8t+c}{2}\right)^2.$$
Hence, the general solution is
$$ y =\left(\frac{8t+c}{2}\right)^2.$$