Perpendicular lines have opposite, reciprocal slopes. Which equation has the opposite, reciprocal slope of your equation and has (-2,1) as a solution (meaning you plug both points in and it makes the equation true)?

For example...

Is (3,1) on y = 2x + 6?

1 = 2(3) + 6

1 = 6 + 6

1 = 12

0 = 11

Since that's not true, (3,1) is not on the given line.