if two lines are perpendicular, it is true:
[tex]m1\cdot m2=-1[/tex][tex]y=\frac{8}{5}x-4[/tex]So:
[tex]m1=\frac{8}{5}[/tex][tex]\begin{gathered} \frac{8}{5}\cdot m2=-1 \\ \text{Solving for m2:} \\ m2=(-\frac{5}{8}) \end{gathered}[/tex]Therefore, the answer is:
[tex]\begin{gathered} 5x+8y=32 \\ \text{Solving for y:} \\ y=-\frac{5}{8}x+4 \end{gathered}[/tex]