Question

If $a+b+c=11$ and $ab+bc+ac=25$, then find the value of $a^3+b^3+c^3-3abc$.

• A. $503$
• B. $505$
• C. $506$
• D. $509$

Answer 1

The correct option is C $506$

$a^3+b^3+c^3-3abc=(a+b+c)\left[\right(a+b+c{)}^2-3(ab+bc+ca]$

$\Rightarrow 11({11}^2-3\times 25)=11\times =506$