Solution: Diophantine lived for X years.

x = 1÷6x+ 1÷ 12x+ 1÷7x+5+ 1÷2x+4

x=25÷28x+9

x-25÷28=9

3÷28x=9

x=9÷3*28

x=84

A: It can be seen that Diophantu lived to be 84 years old.

(2)

12×7=84 answer: the answer is the product of the largest coprime factors in 12, "6" and "7"-"12× 7 = 84".

Diophantine's father's age: 84× (1÷ 6+1÷12+1÷ 7)+5 = 38 (years old) A: Diophantine's father's age is 38.

3. Diefantu's son died at the age of 84-4=80 (years old) A: Diefantu's son died at the age of 80.