Non-negative real numbers $a, b$ and $c$ satisfy $$a^2+b^2+c^2+70=35ab+7ac+5bc.$$

The least possible value of $a^2+2b^2+3c^2$ can be expressed as $\frac{m}{n}$ where $m$ and $n$ are relatively prime positive integers. FInd $m+n$

So I don't really know how to start on this problem, all I noticed that you can use the factorization $(a+b+c)^2=a^2+b^2+c^2+2(ab+ac+bc),$ other than this, I don't really know how to do this problem. Any solutions and hints would be appreciated!

hellothere Jul 27, 2021