you need to use the point slope form of a line since you have a point and a slope you can do it. Steps are below
recall point slope form of a line is
[tex]y - y1 = m(x - x1)[/tex]
we plug in a point (6,0) and a slope from our line and get
[tex] y - 0 = - 4(x - 6)[/tex]
simplify
[tex]y = - 4x + 24[/tex]
FINAL ANSWER
[tex]y \: int = 24[/tex]