By looking at the graph, it is clear that the function is not linear and not quadratic. You can use points on the graph to test whether it is an inverse variation function.

Begin with the point (1, 4). If the function is an inverse variation, then $\displaystyle{y}=\frac{{k}}{{x}}\usepackage{cmbright}\Huge\$ , and $\displaystyle{4}={\frac{{{k}}}{{{1}}}}\usepackage{cmbright}\Huge\$ , so k = 4. The graph of the function is therefore $\displaystyle{y}={\frac{{{4}}}{{{x}}}}\usepackage{cmbright}\Huge\$ . Other points on the function, such as (2, 2) and (4, 1) fit this function, so you can determine that it is an inverse variation.