Argh i feel stupid lol, searched google couldn't find anyhting. Ok so im doing higher gcse maths and im stuck on this simple question:
I have to find out the gradient of a line using two co-ordiantes. The exact question is as follows
Given that the points P(7,4), Q(9,-2),R(-5,-20) and S(-3,4), show by the means of gradients that PR is perpendicular to QS.
Now i cant just write the answer i need the working, the answer is in the back of my book but i cant copy it and i cant figure it out even with the answer.
Basically all i would want would be the gradient of qs and pr, preferably with the explanation. PLease help this is due tomorrow!!! thanks