Line segment RS is perpendicular to line segment PQ, and the coordinates are R(4, -5), S(-8, 4), P(0, 6), and Q(-3, y). What is the value of y?

Question

Line segment RS is perpendicular to line segment PQ, and the coordinates are R(4, -5), S(-8, 4), P(0, 6), and Q(-3, y).  What is the value of y?

anonymous · Answer

I can do this vectors and higher maths, but I guess you have not learnt that. 
You should graph the points, maybe it helps. I get a pen and paper too

anonymous · Answer

I thought about it and have a way of solving it. 
If they are perpendicular that means that the slope of the two line are the same just with opposite signs. 
Do you know how to get the slope of the line that connects RS?