Respuesta :

m<ABC = m<EBD = 36 (vertical angles)

78 - x + 36 + 3x - 10 = 180 (straight angle)

Now solve for x

78 - x + 36 + 3x - 10 = 180
2x + 68 = 180
     -  68     -68 (subtract 68 on both sides)
2x        =  58
  x        =  29