Answer:
Possible values of fredicos age satisfy 
 where
 where 
 denotes fredicos age.
 denotes fredicos age.
Explanation:
Let 
 denotes fredicos age.
 denotes fredicos age.
Three times the difference of fredicos age and 4, increased by 7 = 

According to the question,

So, possible values of fredicos age satisfy 

Here, 
 denotes fredicos age.
 denotes fredicos age.