Answer:
a+b+c =13
Step-by-step explanation:
[tex]\left\begin{array}{ccccccc}aX^2&+&bX&+&c&=&0\\ \downarrow&&\downarrow&&\downarrow&&\downarrow\\9.X^2&-&2.X &+& 6 &=& 0\end{array}\right \implies \left\{\begin{array}{ccccccc}a=9\\b=-2\\c=6\end{array}\right[/tex]
[tex]\implies a+b+c = 9+(-2)+6\\=9-2+6\\=7+6\\=13\\\\\therefore a+b+c =13[/tex]