Question 1190971
The son's age, b
The man's age, b+4b=5b


The description, {{{(b-5)(5b-5)=175}}}.
You can solve this and decide if it gives a meaningful result.


Factor of 5 is on both sides, so
{{{(b-5)(b-1)=35}}}
and these factors will not give the whole numbers in case you were expecting some.