Write a linear function f with given values

If f(-2)=1 and f(1) = 7, then 2 pts on the str. line are (-2,1) and (1,7).

                                                                                  7 - 1
The slope of the line connecting these 2 pts is m = = 6/3 = 2
                                                                                   1-(-2)

Use the slope-intercept formula.  Let the point be (1,7) and the slope be 2:

7 = 2(1) + b; find the y-intercept, b:

7 = 2 + b, so b = 5, and the equation of this line through the 2 given points is then 

y = 2x + 5 (answer)