help please my teacher isn't the greatest.

Answer:
x = 9.5
Step-by-step explanation:
We see that the entire length of DF is equal to 34. That means segment DE and segment EF must combine to equal 34:
3x - 6 + x + 2 = 34
4x - 6 + 2 = 34
4x - 4 = 34
4x = 38
x = 9.5