I would like someone to give this a quick check, I am really not sure if I am over thinking this question. I got the right ans, just would like a quick check of my method; big thanks in advance. question: [itex]P(-1,5), Q(8,10), R(7,5) & S(x,y)[/itex] are the veritices of the parallelogram PQRS. Calculate the coordinate of S. So all I did was workout the gradient of the line Q & R and applied that backwards from P, which gave the ans y=0 x=-2 which is correct, but I cant get rid of the feeling, that I have done something wrong but not sure what. Is this the correct way to approach this type of question, seems a little basic to me which causes the concern.