1/8y(5y+64)=1/4(20+2y)

1/8y(5y+64)=1/4(20+2y)     multiply both sides by 8 to clear the fractions

y(5y + 64) = 2(20 + 2y)        distribute terms on both sides

5y² + 64y = 40 + 4y           subtract 40 + 4y from both sides

5y² + 60y - 40 = 0               see if we can factor

5(y²  + 12y -8) = 0                divide both sides by 5

y²  + 12y  - 8 = 0                 no factoring available..... using the on-site calculator, we have

$${{\mathtt{y}}}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{\mathtt{12}}{\mathtt{\,\times\,}}{\mathtt{y}}{\mathtt{\,-\,}}{\mathtt{8}} = {\mathtt{0}} \Rightarrow \left\{ \begin{array}{l}{\mathtt{y}} = {\mathtt{\,-\,}}{\mathtt{2}}{\mathtt{\,\times\,}}{\sqrt{{\mathtt{11}}}}{\mathtt{\,-\,}}{\mathtt{6}}\\
{\mathtt{y}} = {\mathtt{2}}{\mathtt{\,\times\,}}{\sqrt{{\mathtt{11}}}}{\mathtt{\,-\,}}{\mathtt{6}}\\
\end{array} \right\} \Rightarrow \left\{ \begin{array}{l}{\mathtt{y}} = -{\mathtt{12.633\: \!249\: \!580\: \!710\: \!799\: \!7}}\\
{\mathtt{y}} = {\mathtt{0.633\: \!249\: \!580\: \!710\: \!799\: \!7}}\\
\end{array} \right\}$$