Plug the slope into m in y=mx+b and then plug in your point and solve for b. You get C
12. Parallel means it has the same slope or the same m, so the -1/2 stays the same and you plug that and your point into the y=mx+b and solve for b again. You get D, y=-1/2x-9
13. Perpendicular means that the slope is the opposite reciprocal so you flip it and multiply it by -1. You then plug that in for your slope and plug in your points and you get A, y=9x+13
