You can put this solution on YOUR website! solve each proportion for the given variable
2x/x+1=a/b-3 ; solve for x
-----
2x/(x+1) = a/(b-3)
---
(2x)(b-3) = a(x+1)
---
x(2b-6) = ax + a
---
x(2b-a-6) = a
----
x = a/(2b-a-6)
================
Cheers,
Stan H.