In this case, Gabriella = x Felicia is 6 years older than Gabriella's age. this makes their equation F = x + 6 Their mother is twice as old as Felicia. this makes their equation M = 2(x + 6) or 2x + 12 Tanya is the mothers age + Gabriella's age. this makes the equation A = 2x + 12 + x = 3x + 12 when you solve the equation you will get the equation 3x + 12, which is the simplified expression that represents Tanya's age.