In the given figure, both lines m and n are parallel.
The co-interior angles are supplementary,
[tex]y+3x+10=180[/tex]Taking variables one side and constant another side.
[tex]\begin{gathered} y+3x=180-10 \\ y+3x=170 \\ y=170-3x \end{gathered}[/tex]Thus, the equation of y is in terms of x.
[tex]y=170-3x[/tex]