Please help me i have so much work to do today

Write an equation for the function that includes the points (1,4/5) and (2,2/3)

Out of 50 students surveyed, 16 have a dog. based on these results, predict how many of the 280 students in the school have a dog.

In order for the function to be linear, what must m be and why? m = 22 because the rate of change is 1. m = 20 because the rate of change is 3. m = 22 because the rate of change is -1. m = 20 because the rate of change is -3.