How to find the y-intercept of this graph? http://i.imgur.com/oPlXhZl.jpg When I got the answer wrong my practice quiz told me that the y-intercept was 30 but I don't know how they got that? Did they multiply 6 by 5? I don't know how to find this.

Question

junhaoz · Answer

from the equation y=mx+b, and since the x intercept is 5, we can get the equation 
0=-6 times 5+b, and b needs to be 30

anonymous · Answer

i still don't understand but i think that's just my fault. thx. :D