Consider the 4 points A(1,5), B(-4,6), C(0,0), D(-12,12). Find the gradients of the lines:

(a) AB;

(b) CD;

(c) BD.

a. m = *y2-y1)/(x2-x1) = (6-5)/(-4-1) = -1/5.

Use same procedure for part b, and c.