Let the age of one friend be x years.
then the age of the other friend will be (20 - x) years.
4 years ago,
Age of 1st friend = (x - 4) years
Age of 2nd friend = (20 - x - 4) = (16 - x) years
According to question,
(x - 4) (16 - x) = 48
16x−x2−64+4x=48
−x2+20x−112=0
x2−20x+112=0
Comparing this equation with ax2+bx+c=0, we get
a=1,b=−20 and c=112Discriminant=b2−4ac=(−20)2−4×112=400−448=−48b2−4ac<0
Therefore, there will be no real solution possible for the equations. The given situation is not possible.