I think you forgot to add a photo
Y=3x−9
y=3(0)-9
y=9
Now plug in y to solve for x.
y=3x−9
9=3x-9
18=3x
6=x
The x-intercept is (6,0)
Answer: 
Step-by-step explanation:
Given
Speed of boat 



5x20=100 100+200=300 or atlas what i think if this is wrong i am sry but if isn't I'm glad I'm able to help ^u^