redox reactions!!!!!?

Question

How to you find the oxidation half reaction and the reduction half reaction for these equations.

2H2 + O2 --> 2H2O

Cu + 2AgNO3 --> Cu(NO3)2 + 2Ag

Answer 1

H2 ----> 2H+ + 2e-
O2 + 2H2O + 4e- -----> 4OH-

Double the first one and add it to the second one. Add H+ and OH- ions together to make water. You can cancel most of the water out then.

Cu -----> Cu2+ + 2e-

Ag+ + e- ----> Ag

Double the second one and add it to the first one.