x - age of Mikhail's
3x - age of Gabrielle (three times Mikhail's age)
x + 3x = 56
4x = 56 |:4
x = 14 <-- age Mikhail
3 * x = 14 * 3 = 42 <-- age Gabrielle
As is clear from the job three times the 14 to 42 by adding 14 gives 56, which is behind what they have in total.