The equation of a line given two points can be calculated by the formula:
[tex]\begin{gathered} \frac{y_2-y_1}{x_2-x_1}=\frac{y-y_1}{x-x_1} \\ \text{Given the two points on the graph to be} \\ (x_1,y_1)=(0,0) \\ (x_2,y_2)=(1,9) \end{gathered}[/tex]
Plugging in the coordinate values into the formula, we have
[tex]\begin{gathered} \frac{9-0}{1-0}=\frac{y-0}{x-0} \\ \frac{9}{1}=\frac{y}{x} \\ y=9x \end{gathered}[/tex]
Therefore, the equation of the line given is
[tex]y=9x[/tex]
