There are lots of different methods for solving this.  Which way
are you studying at the present? I'll help you do it if you are
interested in learning the method.  But if all you want is to fool 
your teacher temporarily into thinking you know something that you 
don't, then the answer is



If you want help with the method to get that answer, you can tell 
me about it in the thank-you note form below and I'll get back to
you by email. No charge ever.  I do this as a hobby.

Edwin