How do you balance the equations below:

I completed them but my textbook doesn't have a page to check you're work.

Balance the equations below please:

a : ___Al(s) + ____ O2 (g) ----> _____Al2O3 (s)


b: ____C8H16 (l) + ____ O2 (g) ------> _____ CO2 (g) +_____H20 (g)


c: ______ NH3 (g) + ______ O2(g)-----> _____ NO(g) + ______H2O (l)


Thank-you

a : 4 Al(s) + 3 O2 (g) ----> 2 Al2O3 (s)


b:C8H16 (l) + 12 O2 (g) ------> 8CO2 (g) +8H20 (g)


c: 4 NH3 (g) + 5 O2(g)-----> 4 NO(g) +6 H2O (l)

a. 4Al + 3O2 ---> 2Al2O3
b. C8H16 + 12O2 ---> 8CO2 + 8H2O
c. 4NH3 + 5O2 ---> 4NO + 6H2O

a)4Al + 3O2 ------> 2Al2O3

b) C8H16 + 12O2 -------> 8CO2 + 8H2O

c) 4NH3 + 5O2 ---------> 4NO + 6H20