Write an equation for the statements -

a. In 2 years, Casey will be 3 times as old as Mary

b. Casey's age next year

c. Mary's age next year

What you want :

Write an expression for the statements -

"In 2 years, Casey will be 3 times as old as Mary"
let Mary's present age be x
then in 2 years, Mary will be x+2, and Casey will be 3(x+2)

So Casey's present age is 3(x+2) - 2
one year from now Casey will be 3(x+2)-2 + 1 = 3x + 5

Mary's age next year = x+1