SOLUTION: When the sum of 6 and twice a positive number is subtracted from a square of the number, 0 results. Find the number.

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: When the sum of 6 and twice a positive number is subtracted from a square of the number, 0 results. Find the number.      Log On


   

Question 757133: When the sum of 6 and twice a positive number is subtracted from a square of the number, 0 results. Find the number.
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
6%2B2n-n%5E2=0

%28-1%29%28-n%5E2%2B2n%2B6%29=0%2A%28-1%29
n%5E2-2n-6=0 not factorable.

Use solution to quadratic equation:
n=%282%2B-sqrt%284-2%28-6%29%29%29%2F2
n=%282%2B-sqrt%2816%29%29%2F2
n=%282%2B-+4%29%2F2

n=-1 or n=3