Here are the steps to solve this problem.
1) First find the length of BC ; (consider the traingle ABC)
2) Then find the length BD ; (consider the traingle BDC)
3) Now you can find the length BE ; (considering the fact that BD=DE)
4) Find the CE ; (consider the traingle BCE)
5) Finally considering the traingle CFE you can find X.
Hope these ideas will help you.