Use `solve`output to create a function    
   Hi there,
I want to use the ouptut of solve to create a function from it. 
My system depends on some parameter, say $a$, it is a tiny linear system $2\times 2$, and I know there is always a solution. The right-hand term also contains some $a$ into it. What I want to do is to use the first and the second component to buy functions, calle them x1(a) and x2(a)  that I will call later. I tried something like 
var("v1, v2, a")
Sols = solve([v1+a*v2 == a, -a*v1 + v2 ==0],[v1,v2])
x1(a) = Sols[0][0].rhs()
x2(a) = Sols[0][1].rhs()
This gives the expected expressions for x1 and x2 but I cannot use these to do further computations, for instance, using x1(1) wont evaluate the expression when $a=1$, as I would expect. 
The very precise example above is not what I actually want to handle, my actual system is actually more complex.
Many thanks!
 
Works for me on Sage 8.1.rc2:
Works ditto for me on Sage 8.0.