If they are parallel:
[tex]m1=m2[/tex]Since the slope for y=-5x+8 is m1=-5:
[tex]m2=-5[/tex]Let:
(x1,y1)=(0,2)
Using the point-slope equation:
[tex]\begin{gathered} y-y1=m(x-x1) \\ y-2=-5(x-0) \\ y-2=-5x \\ y=-5x+2 \end{gathered}[/tex]---------------------------------------------------------------------------------------
If is perpendicular to the line equation y=1/2x-3:
[tex]\begin{gathered} m1\times m2=-1 \\ \text{Where:} \\ m1=\frac{1}{2} \\ \frac{1}{2}\times m2=-1 \\ m2=-2 \end{gathered}[/tex]Let:
(x1,y1)=(-5,2)
Using the point-slope equation:
[tex]\begin{gathered} y-y1=m(x-x1) \\ y-2=-2(x-(-5)) \\ y-2=-2(x+5) \\ y-2=-2x-10 \\ y=-2x-8 \end{gathered}[/tex]