Is this equation completely balanced?

2C8H8 + 25O2 8CO2 + 18H2O

In order to say that the chemical equation is balanced, it is important to note that the number of atoms of each element in the product side and the reactant side should be equal.

Reactant

C = 16

H = 16

O = 50

Product

C = 8

H = 36

O = 34

Therefore, the equation is not balanced. Hope this answers the question. Have a nice day.