Those choices all pass through (2,2) so substituing that does no good. We have to know two things: 1. y = mx+b. when you see y = x+ or y= x- where there are numbers in those boxes that the number in the first box is always the slope. 2. If one line has the slopethen a line perpendicular to it has the slope . "We flip it and change its sign" [That's because : a. We flip it because the 'rise' on one line becomes a 'run' on a line perpendicular to it and vece-versa. and b. We change the sign because if a line goes uphill to the right it has a positive slope. A line perpendicular to it goes downhill to the right and has a negative slope.] So we look at and see that its slope is , So we flip it and change the sign and get which simplifies to . Then we look through the list of choices and find the one that has a as a coefficient of x. Then we see that the only choice is D. Edwin