Maths binomial probability help?

The question is:

I've gone through the whole textbook chapter and have no idea on how to get these answers

If x=1, you must have thrown a head as you win on the first attempt
if x=2, you must win on the second throw so ...
...

ohhh it's the probability of not throwing a head on the first one then doing it on the second one, and the probability of not throwing a head is (1 - p) and throwing a head is p so (1 - p)p is the probability of not throwing a head then throwing a head

Sounds right, and x=3 is obviously a combination of TTH or TTT.
If you draw the corresponding "tree" is almost a single branch, which gets longer only if you throw T. Its similar to a geometric distribution if you want to look it up.

but shouldn't x = 3 just be (1 - p)²p ? isn't that the probability of 2 tails and a head? I don't really get why (1 - p)^3 is added on at the end.