Answer:
OB - Older Brother
YB - Younger Brother
A) OB -YB = 4
B) OB * YB = 96
B) OB = 96 / YB
Multiplying A) by -1
A) -OB + YB = -4 then we add B)
B) OB = 96 / YB
YB = -4 + 96 / YB
Multiplying both sides by YB
YB^2 = -4YB +96 then re-arranging
YB^2 + 4YB -96 = 0 solving by quadratic equation
AS OF 5 years AGO:
Younger Brother's age = 8
Older Brother's age = 12
NOW THEIR AGES ARE:
8 + 4 = 12 YB and
12 + 4 = 16 OB
Explanation: