Question 982757
.
M=man; S=son
.
M=5S
.
(M-4yrs)(S-4yrs)=52yrs
(5S-4yrs)(S-4yrs)=52yrs
5S^2-24S+16=52
5S^2-24S-36=0
(5S+6)(S-6)=0
5S+6=0 or S-6=0
5S=-6 or S=6
S=-5/6 or S=6 
ANSWER 1: Son is 6 years old
M=5(S)=5(6yrs)=30 years old 
ANSWER 2: The man is 30 years old.
.
CHECK:
(M-4yrs)(S-4yrs)=52yrs
(30yrs-4yrs)(6yrs-4yrs)=52yrs
(26yrs)(2yrs)=52yrs
52yrs=52yrs