Find a missing coordinate using slope

Question

(9,-9) and (-2,w) has a slope of -1 . What is the value of w

Answer 1

(9,-9), (-2,w)

slope is "rise over run" or the change in y coordinates divided by the change in x coordinates: (w--9)/(-2-9) = (w+9)/-11 = -1

w+9 =11, w =11-9 =2

w=2

(9,-9) (-2,2) have a line through them with slope = -1

(2--9)/(-2-9) = 11/-11 = -1