The equation of a line in its slope-intercept form is
[tex]\begin{gathered} y=mx+b \\ \text{ Where m is the slope of the line and} \\ b\text{ is the y-intercept} \end{gathered}[/tex]So, in this case, you have
[tex]\begin{gathered} m=\frac{4}{3} \\ b=0 \end{gathered}[/tex]Now, you have
[tex]\begin{gathered} y=mx+b \\ \text{ Replacing} \\ y=\frac{4}{3}x+0 \\ y=\frac{4}{3}x \end{gathered}[/tex]Therefore, the equation of the line will be:
[tex]y=\frac{4}{3}x[/tex]