SIMPLE GEOMETRY QUESTIONS ABOUT LINES

Here's the question:
Find DF if D is between E, and F, ED= 6x-4, DF = 3x+5 and EF = 46.

There is no picture but it's multiple choice. My choices are: 22, 26, 28, or 20.

I figured out that: E is the first point, D is the middle point and F is the last point.


I thought I would have to do it like this:
For DF: 3x+5 = 46

And then I would subtract 5 and then divide 41 by 3. That isn't the case? Cause I got like 13.4444444 etc!

I'm so confused!): please help! Thanks

(6x - 4) + (3x + 5) = 46
9x + 1 = 46
9x + 1 - 1 = 46 - 1
9x = 45
9x/9 = 45/9
x = 5

DF = 3x + 5
DF = 3(5) + 5
DF = 15 + 5
DF = 20

It should be:
DF=ED+DF
Simplify and find x.
Then substitute that number for x in the equation for DF (3x+5)
good luck!

E------------D----------------------F
|..6x-4......|
...............|......3x+5..........|
|.................46.................|

so EF=46= ED+DF= 6x-4+3x+5