The formula is,
(y [the second one] - y[the first one]) / (x [the second one] - x [the first one])
The first x=5, first y=12, second x=30, second y=72
Plug the numbers in, to get
(72-12) / (30-5)
Now just crunch it out.
(60) / (25)
=2.4
This is your answer.
Hope it helped!
