You can put this solution on YOUR website!
One way to solve this is graphically.
Plot the given points (x, y) on a sheet of graph paper on which you drawn the x-axis (horizontal) and the y-axis (vertical).
You should see a graph like this:
To get the corresponding equation, you need to know two things about the line on the graph: its slope (m) and the y-intersection (b).
The y-intersection is where the line crosses the y-axis and this is at (0, 2) and the slope (m) can be determined by picking any two points on the line and using the following formula:
You can use any two points from the given list, say (-1,1) and (3, 5) as the x's and y's in the formula.
The slope is 1.
Now use the "slope-intercept form of a linear equation:
and you get:
So yes, it is a function.