True, Fe (iron) has 2 on the left side and on the other side as well. C (carbon) has 3 on the left and 3 on the other. O (oxygen) has 6, 3 for the first part and another 3 because of the reciprocal in the beginning of the equation. On the other side O has 2 and it's multiplied by the reciprocal 3 which is 6
we know that
The vertex of the function
is the point 
The vertex of the function
is the point 
The x-coordinate of the vertex is equal to h
the y-coordinate of the vertex is equal to k
so
the value of h is 
the value of k is 
the equation is

therefore
<u>the answer is the option a</u>

Total number of marbles=5+3+4=12
Probability of picking a red marble =5/12
Can you show me the diagram