Question 1179645
a father is 30years old and his son is 14 years; when in the past was the product of their age 80?

Let the product of their ages be 80, x years ago

(30-x)(14-x) =80

420 -30x-14x+x^2=80

x^2-44x+340=0
(x - 34)(x - 10)=0

x=34 or 10

x=34 is absurd
so x=10