this week I learn Slope of line and Slope formula. I know what is rise and run RISE is Y and RUN  is X. slope formula is RISE/RUN = Y1-Y2/X1-X2. such as A(5,15), B(5,5) Slope is 15-5/5-5=10.the points (2,7),(0,5) and (-1,2) collinear. the points (5,5) and slope is 10. Y-5/X-5=1/-10