We can find the y-intercept by writing the slope-intercept form of the equation. For that first we need to find the slope of the given line.
[tex]Slope=m= \frac{17-3}{10-6}= \frac{7}{2} [/tex]
Using the slope m =7/2 and a point (6,3) we can write the equation of the line as:
[tex]y-3= \frac{7}{2}(x-6) \\ \\
y= \frac{7x}{2}-21+3 \\ \\
y= \frac{7x}{2}-18[/tex]
The equation above is in the slope intercept form.Coefficient of x is the slope and constant term is the y-intercept.
So, the y-intercept for the line is -18. Therefore, option C is the correct answer
