I worked the problem by hand. First I used the equation y=mx+b to find the rule for the function. To find m which is the same as the slope you use the change in y divided by the change in x. Or the change in output divided by the change in input. The two points or coordinates used were (-2,-4) and (1,-1). Once you have the slope you use y=mx+b and substitude y by any value of y (-4 or -1) and m is the slope calculated and x would be the corresponding x to the y value used (if -4 was chosen for y then -2 would be used for x). This will be used to calculate b.
