f(x)=2x
1) In this question the best way to tackle this is to analyze the f(x) column at first.
Based on that, we can tell that this is a linear function.
2) Now, let's pay attention to where x=0, we can see that y=0 as well so this is a linear function whose y-intercept is at the origin (0,0). The next step is to find the slope. We need to pick two points (0,0) and (-1,-2)
[tex]m=\frac{-2-0}{-1-0}=\frac{-2}{-1}=2[/tex]As the y-intercept is at (0,0) and the slope is 2. Thus the rule for this function is:
[tex]f(x)=2x[/tex]