If the line is perpendicular to:
[tex]y=-2x+1[/tex]the we know that the slope will be the negative reciproc of the slope so the new slope is:
[tex]m=\frac{1}{2}[/tex]So the equation is:
[tex]y=\frac{1}{2}x+b[/tex]So we can replace the coordinate (-2,-4) and solve for b so:
[tex]\begin{gathered} -4=\frac{1}{2}(-2)+b \\ -4+1=b \\ -3=b \end{gathered}[/tex]So the final equation is:
[tex]y=\frac{1}{2}x-3[/tex]