First, we must find the slope using the equation
[tex]\frac{y_{2}-y_{1} } {x_{2}-x_{1}}[/tex]
We can substitute in our points and will get
[tex]\frac{18-6}{5-3} =\frac{12}{2} = 6[/tex]
This means that our slope is m=6.
We can now use the point slope form to find the equation of the line. The equation for this is [tex]y-y_{1} =m(x-x_{1})[/tex]
Now we can substitute in one of our point, (3,6) in this case.
[tex]y-6 = 6(x-3)[/tex]
this simplifies to
[tex]y= 6x-12[/tex]
now we can swap y for f(x) to put it in function notation
this means that the answer is [tex]f(x) = 6x-12[/tex]; which means that the answer is b
