Balance Redox Reaction, I have no clue how to do this?

Question

The question is: Balance the redox reaction which occurs in acid solution.

Fe2+(aq) + Cr2O72-(aq)-->Fe3+(aq)+Cr3+(aq)

If you can help me with this I'll gladly choose your answer as the best one.

Answer 1

Fe2+ goes from +2 to +3
Cr goes from +6 to +3
The balanced equation is
6 Fe2+ + Cr2O72- + 14 H+ --> 6 Fe3+ + 2Cr3+ + 7H2O

Answer 2

The way to balance Redox Reaction is to first write out the half reactions:
Fe2+(aq) -->Fe3+ + e-
Cr2O72-(aq) + 6e- + 14 H+ -->2Cr3+(aq) + 7H2O
Hence:
Cr2O72-(aq) + 6Fe2+(aq) + 14 H+ -->6Fe3+(aq) 2Cr3+(aq) + 7H2O

Answer 3

Fe2+ -> Fe3+ + e
Cr2O72- + 14H+ 6e -> 2Cr3+ + 7H20

overall:

6Fe2+ + Cr2O72- + 14H+ -> 6Fe3+ + 2Cr3+ +7H20