By definition, a function is a relation in which each input value (x-value) has one and only one output value (y-value).
In this case, you need to find all input values for the following output value:
![f\mleft(x\mright)=-5](https://img.qammunity.org/2023/formulas/mathematics/college/qt2i523qf93zlej2rhmle96ca39ew7rqpk.png)
Knowing that the output values are the y-values, you can rewrite it as:
![y=-5](https://img.qammunity.org/2023/formulas/mathematics/high-school/49njks2kl4v7di0m489rm5i4xohp6pw280.png)
Then, you can find the points with -5 as their y-coordinate. For the blue graph, you get:
For the red function, you can draw a horizontal line. See below:
Notice that the x-coordinate of the point whose y-coordinate is -5, is between -3 and -4, so you can set up that:
![x\approx-3.5](https://img.qammunity.org/2023/formulas/mathematics/college/cm6qv7eoogx2eabinwak9axdd1hpn8xsja.png)
Therefore, the answers are:
![-4,0,-3.5](https://img.qammunity.org/2023/formulas/mathematics/college/twc2ezifdh7qcgetna1es362jwnra4nu3x.png)