We can see that the solubility of salt increases with increasing temperature. This happens with most substances.
To find out the maximum mass of copper sulfate that can be dissolved in water at these temperatures, just interpret the graph.
Considering Y-axis as g copper sulfate/100 g water and the X-axis as the temperature in °C:
1) a: 0 °C - 14 g of copper sulfate/100 g of water
b: 50 °C - 34 g of copper sulfate/100 g of water
c: 90 °C - 66 g of copper sulfate/100 g of water
2) From the graph, we can infer that temperature affects the solubility of the salt.