SOLUTION: Noelle is 5 years younger than her sister Aya. The difference of the square of Aya’s age and twice the square of Noelle’s age is 1. How old are the two sisters?

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Question 1187064: Noelle is 5 years younger than her sister Aya. The difference of the square of Aya’s age and twice the square of Noelle’s age is 1. How old are the two sisters?
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
If you start with system%28A=n%2B5%2CA%5E2-2n=1%29, substitute for A, then after a few steps you can get:

n%5E2-10n-24=0
and discriminant is ,... 14%5E2.

n=%2810%2B-+14%29%2F2
and one of this will work but not the other one.
You can finish.



Noelle, 12
Aya, 17