If you want some help for your homework, please don't just post an equation and ask it to be solved. Mathematics is a precise science and tasks should be (and usually are) defined precisely. So, please, if you post a problem, define as precise as you can what the problem is and how it needs to be solved.
Put simply, we're not here to do your homework for you. We'll help, but we'll only help those that help themselves.
Also, I think this goes without saying, but don't answer a question unless you have the correct solution AND explanation.
You both are right.