Answer:
DE = 11
Explanation:
DE = x + 7
EF = 7
DF = 4x + 2
DF = DE + EF (segment addition postulate)
Substitute
4x + 2 = x + 7 + 7
4x + 2 = x + 14
Collect like terms
4x - x = -2 + 14
3x = 12
Divide both sides by 3
x = 12/3
x = 4
✔️DE = x + 7
Plug in the value of x
DE = 4 + 7
DE = 11