Respuesta :
x is Camila's age now,
3x is Brianne's age now.
(x+4) is Camila-s age 4 years from now,
(3x + 4) Brianne's age 4 years from now.
Four years from now she(Brianne) (3x+4) will be just two times as old a Camila (x+4).
3x + 4 = 2(x+4)
3x+4 = 2x +8
3x - 2x= 8 - 4
x =4 years old is Camila's age now.
3x=3*4 =12 years old Brianne's age now.
