Let Jenny = J
Let Mica = M
J = M + 4
Now you have to represent 5 years ago
J - 5 = 2*(M - 5)
J - 5 = 2M - 10 Substitute J = M + 4 Into this equation
M + 4 - 5 = 2M - 10 Combine terms on the left
M - 1 = 2M - 10 Add 10 to both sides
M - 1 + 10 = 2M Combine one the left
M + 9 = 2M Subtract M from both sides
9 = 2M - M
9 = M Answer Miki
J = M + 4 Substitute Miki's age for M
J = 9 + 4 Answer Jenny
J = 13
Answer:
Jenny = 13
Mika = 9