Respuesta :
Answer: The number to the left of AC should be 6.
Explanation: The balanced chemical reaction is one in which the number of atoms of each element on the reactant side must be equal to the number of atoms on product side.
The given equation [tex]A_2B + DC_3 \rightarrow AC + D_2B_3[/tex] is unbalanced as the atoms on the reactant side are not same as number of atoms on product side. This equation is called as skeletal equation.
The balanced chemical equation is :
[tex]3A_2B + 2DC_3 \rightarrow 6AC + D_2B_3[/tex]
Thus the number to the left of AC is 6.