Can you solve this now?
To get the rest of the equation for the line you can use the slope-intercept form:
Plug in either point and the slope you just calculated and solve for b.
I am personally against numbers written in this form, though I fully understand why they are useful. But I find that they rather confuse things by the time a student reaches their first Algebra course.
Anyway, I would convert these numbers to improper fractions:
You should be able to finish this now.
Someone else is going to have to help you with the last problem.