Answer:
The y-intercept b for the derived equation is;
[tex]b=-7[/tex]Explanation:
Given that the line passes through the point (4,-9) and has a slope of -1/2;
[tex]\begin{gathered} \text{slope m=-}\frac{1}{2} \\ \text{ point (4,-9)} \end{gathered}[/tex]Applying the point-slope form of linear equation;
[tex]y-y_1=m(x-x_1)[/tex]substituting the slope and the given point;
[tex]\begin{gathered} y-(-9)=-\frac{1}{2}(x-4) \\ y+9=-\frac{1}{2}x+\frac{4}{2} \\ y+9=-\frac{x}{2}+2 \\ y=-\frac{x}{2}+2-9 \\ y=-\frac{x}{2}-7 \end{gathered}[/tex]Comparing it to the slope intercept form of linear equation;
[tex]y=mx+b[/tex]where;
m = slope
and b = y-intercept
Therefore, the y-intercept b for the derived equation is;
[tex]b=-7[/tex]