Slope-intercept form of a straight line is given by:
[tex]\begin{gathered} y=mx+b \\ \text{Where:} \\ m=\text{Slope} \\ b=y-intercept \end{gathered}[/tex]As you can see:
For:
[tex]\begin{gathered} y=-\frac{4}{7}x+3 \\ m=-\frac{4}{7}=\text{Slope} \\ b=3=y-\text{intercept} \end{gathered}[/tex]