Respuesta :

Since E is the midpoint, DE and EF are the same length.
Set the equation DE and EF equal to each other and solve for x.
2x + 4 = 3x - 1
x = 5
Then plug in 5 to find the length.
DE = 2(5) + 4 = 14
EF = 3(5) - 1 = 14
DF = DE + EF = 28