From one set of equations to another

Hi.
How does one get from the upper pair of equations to the lower pair of equations? What has been done to manipulate the upper equation to the fom of the lower ones?

http://s1328.photobucket.com/user/fselja…


Thanks!

Hi.
I am not going to write the solution step by step for you but I will tell you the steps:

1) Split up the fractions in the upper part of the pic, some have a double minus so now they will have a plus, for instance: -(v1/R2) +(v2/R2) and so on.
2) You need to solve for v1 and v2, that is what has been done in the lower part of the picture. Factor v1 and v2 out and leave R inside the bracket.

Hope this helped.