Solution: x-[(1÷ 6) x+(1÷12) x+(1÷ 7) x+5+(1÷ 2).
x-[ 1/6x+ 1/ 12x+ 1/7x+5+0.5x+4]= 0
x-[25/28x+5+4]=0
x-25/28x-9=0
x-25/28x=9
3/28x=9
x=84
A: It can be seen that Diophantu lived to be 84 years old.
2. How old did Diophantu become a father?
84× (1÷ 6+1÷12+1÷ 7)+5 = 38 (years old)
A: Diophantu became a father at the age of 38.
3. Diefantu's son died of age:
84-4=80 years old
A: When my son died, Diophantu was 80 years old.
See /p-43907390.html for the specific answer. Tip: The practice part of 3.4 is omitted here. Find it yourself. Even the question number is wrong, but the answers are all right.