To determine which equation describes the function shown in the mapping diagram, we need more information about that diagram, such as the specific pairs of \(x\) and \(y\) values that are indicated.
Since I cannot see the image, I can't provide a definitive answer. However, if you can share specific values or relationships conveyed in the mapping diagram, I'd be happy to help you deduce which equation fits.
Please provide the \(x\) and \(y\) pairs or describe the mapping more thoroughly!