Question 395673
Let A = Alex's age and F = Frank's age.
A = F+6  "Alex is 6 yrs. older than Frank."
A+F = 50  ""The sum of their ages is 50." Substitute for A, A = F+6 and solve for F.
(F+6)+F = 50
2F+6 = 50
2F = 44
F = 22 and A = 22+6 = 28.
Alex is 28 years old and Frank is 22 years old.