What is the rate of change of the linear function that has a graph that passes through the points (9, 3) and (19, -17)?

Answer 1

slope = "rise over run" the difference in y coordinates divided by the corresponding difference in x coordinates

(3- - 17)/(9-19) = 20/-10 = -2 = rate of change

y=-2x + b is the line with slope =-2, solve for b by plugging in either point

-17 = -2(19) + b

b = -17 +38 = 21

y=-2x + 21 is the line through the two points, with slope = rate of change= -2