Explanation:
The constant of proportionality can be calculated as:
[tex]\frac{y}{x}[/tex]For every point (x,y) in the line.
So, if we replace (x, y) by point (2,2) or by point (-3,-3), we are going to get:
[tex]\begin{gathered} \frac{x}{y}=\frac{2}{2}=1 \\ or \\ \frac{x}{y}=\frac{-3}{-3}=1 \end{gathered}[/tex]So, the constant of proportionality is 1.
Answer: 1