Answer:
x = 12
Step-by-step explanation:
The length of the midsegment is the average of the lengths of the other two.
5x -20 = ((4x +2) +(2x +6))/2
5x -20 = 3x +4 . . . . . . . . . . . . simplify
2x = 24 . . . . . . . . . . . . . . . . . . add 20-3x
x = 12 . . . . . . . . . . . . . . . . . . . . divide by 2
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Check
The three segment lengths are ...
top: 2·12 +6 = 30
midsegment: 5·12 -20 = 40
bottom: 4·12 +2 = 50
Indeed, 40 is the average of 30 and 50.
