four years agoslyvia was two thirds as old as alex was then. four years from now, she will be four fifths as old as alex will be. how old are sylvia and alex now?

Let S be SylVia's current age. Let A be Alex's current age. You have two equations to be solved simultaneously.
S-4 = (2/3)(A-4)
S+4 = (4/5)(A+4)

Subtract the fist equation from the second to eliminate s as a variable.
8 = (2/15)A + 16/5 + 8/3 = (2/15)A + 88/15
Continue the solution yourself