Slope intercept form is y=mx+b because m=slope and b=y-intercept hence "slope intercept form"...
m=deltay/deltax=(0-5)/(-9--6)=-5/-3=5/3 so far we have now:
y=5x/3 +b, using any point, I'll use (-9,0) we can now solve for b or the y-intercept...
0=-9(5)/3 +b
0=-15+b, so b=15 and our line is:
y=5x/3 + 15 or more neatly
y=(5x+45)/3