The parallel lines have the same slope.
Calculate the slope:
[tex]m=\dfrac{\Delta y}{\Delta x}[/tex]
Look at the picture. Substitute:
[tex]m=\dfrac{-2}{-1}=2[/tex]
We have the point (0, -1).
The point-slope formula:
[tex]y-y_1=m(x-x_1)[/tex]
Substitute:
[tex]y-(-1)=2(x-0)\\\\y+1=2(x-0)[/tex]
