Respuesta :

altavistard
The trick here is to recognize that triangles ABE and CDE are similar.

Because they're similar, 14/18 = 3x/(4x-1).
                                
Then 14(4x-1) = 18(3x).  Multiplying as indicated, 56x - 14 = 54 x.

Solving for x:  2x = 14, and x = 7