I figured the answer out but didn't post here as this section of the forum seemed pretty dead.
The part of the solution I was having trouble figuring out comes from:
for (imagCoord = 1.2; imagCoord >= -1.2; imagCoord -= 0.05)
for (realCoord = -0.6; realCoord <= 1.77; realCoord += 0.03)
you divide by 79 and 48 as this gives you 0.05 and 0.03.
In the end I coded out the answer and worked through it but I never would of come up with that myself. I just moved on to chapter 5 and refer back to chapter 4 when I need to.
It would be helpful if the answers came with explanations to make things easier to grasp firstime around as although I can understand what it does and how it achieves it, there is no explanation as to why that method was chosen as my solution was completley different and ended up doing the same thing. Most likely not as well but it still worked.