Explanation:
red y = -3/2 x - 3 m = -3/2 (y2-y1) / (x2 - x1) b = -3
blue y = 2x + 3 m = 2 rise/run b = 3
black your turn m = ? (0, -1) and (3, 0) two points on the black line
m = ? (y2-y1) / (x2 - x1) = (0-(-1)) / (3 - 0) = (0+1)/(3-0)
m = ?
b = the y value when x = 0, which is one of the points