We know that the line passes through (1,4) and it has a slope of 9.
We use the point-slope formula.
[tex]y-y_1=m(x-x_1)[/tex]Where,
[tex]\begin{gathered} x_1=1 \\ y_1=4 \\ m=9 \end{gathered}[/tex]Replacing these values, we have
[tex]\begin{gathered} y-4=9(x-1) \\ y-4=9x-9 \\ y=9x-9+4 \\ y=9x-5 \end{gathered}[/tex]