AoPS Wiki talk:Problem of the Day/September 18, 2011

Revision as of 08:01, 18 September 2011 by Negativebplusorminus (talk | contribs) (Created page with "=Solution= We see that for positive <math>x</math>, <cmath>f(x)=\sqrt{(x^3+3x+0)(x^2+3x+2)+1}=\sqrt{((x^2+3x+1)-1)((x^2+3x+1)-1)+1}=\sqrt{(x^2+3x+1)^2}=\boxed{x^2+3x+1}</cmath> a...")
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Solution

We see that for positive $x$, \[f(x)=\sqrt{(x^3+3x+0)(x^2+3x+2)+1}=\sqrt{((x^2+3x+1)-1)((x^2+3x+1)-1)+1}=\sqrt{(x^2+3x+1)^2}=\boxed{x^2+3x+1}\] and thus $a+b+c=\boxed{5}$.