Let \(f(x)=3x+2\)and \(g(x)=ax+b\), for some constants \(a\) and \(b\). If \(ab=20\) and \(f(g(x))=g(f(x))\)for \(x=0,1,2\ldots 9\), find the sum of all possible values of \(a\).
The sum of all possible values of a is 10.
+19 
