Solve[{((1/(1/50+1/R2))/(1/(1/50+1/R2)+R1))^2=1/10,1/(1/((1/50)+(1/R2))+R1)+1/R2=1/50},{R1,R2}]

Uh oh! Wolfram|Alpha doesn't run without JavaScript.

Please enable JavaScript. If you don't know how, you can find instructionshere.Once you've done that, refresh this page to start using Wolfram|Alpha.