Respuesta :

12/3-6 should be the equation you use to solve
So your sister is 2
the equation is
[tex]3x + 6 = 12[/tex]


and the solution is :
[tex]3x + 6 = 12 \\ 3x = 12 - 6 = 6 \\ x = \frac{6}{3} = 2[/tex]



good luck