The 9 is in the one hundred thousand's place
-x^2 - 2x - 5=0
-(x^2 + 2x + 1) -4=0
(x +1)^2= -4
=> Impossible. There is no x
Answer:
Age of Mark
years
Age of Mark's dad
years
Age of Mark's sister
years
Step-by-step explanation:
Let age of Mark be
years.
Mark's dad is three times older than Mark
Age of her Mark's dad 
Mark's sister is 2 years younger than Mark
Age of Mark's sister
years
The sum of their ages is 48.

Age of Mark
years
Age of Mark's dad
years
Age of Mark's sister
years