We can say that we have two points of the graph: (7, 2.45) and (9,3.15)
therefore we can calculate the slope of the function
[tex]m=\frac{3.15-2.45}{9-7}=\frac{0.7}{2}=0.35[/tex]so the equation is
[tex]\begin{gathered} y-2.45=0.35(x-7) \\ y=0.35x-2.45+2.45=0.35x \end{gathered}[/tex]In conclusion we have that the equation is
[tex]y=0.35x[/tex]