you can do it with a tree diagram. also since you have .5 chance of getting either tails or heads
it would be: E(X) = 1/2 * ( 1++2+3+4+5+6) -----> since you have 6 trials which is equals to = E(x) = 10.5
If you are going to try to help, please at least understand the question.
Look that how absurd your above answer is.
There are only six trials. So how can the expected value be 10.5?