Expanding and Simplifying Varley Bridge Equations

[casper12]

Hi this question is asking to show how multiplying the brackets of the first equation can result into the second equation, I think I have been looking at it for far to long as I can not seem to work it out.

any pointers would be much appreciated.

 

[Merlin3189]

It seems simple. You only need to get rid of the R_c + R_l bracket, leaving the first resulting term alone (keep it for the final result), open up the second term, then bring R_l across and incorporate it into that second term result, simplify it and there you are.

If you show your progress so far I can be more specific perhaps.