What is missing from the solubility graph shown on the right

the name and the units of the vertical axis.

Explanation:

As you see the horizontal axis shows that the independent variable is Temperature and that it is reported in °C.

That kind of information is necessary to be shown to understand the graph. Given that the equation states that it is a solubility graph, we know that the vertical axis shows solubility, but each axis must show the name. Furthermore, we do not know the unit of measure, so when we read a number we do not know if it is g/cm^3, kg/liter, ppm, g/kg, or any other unit.

Abbreviated as mg-25.