1) Let's find the equation of the line. firstly calculating the slope
2) Now that we have found the slope, let's find the linear coefficient
by plugging into the slope-intercept form, one of those points. Usually with the least value.
(3,6)
y=mx+b
6=6(3)+b
6=18+b
6-18=b
b=-12
3) Writing that as a function, we have:
f(x) =6x-12