I think you should do this way (but I'm not sure because I don't know what these letters represent) :
solve(first equation and second equation, [x,y])
where x and y are the variables.
I put it initially, but it seems that it doesn't look useful without it... I don't know what ilde and ucde represent. But if you're dealing with variables containing more than one letter in their name, I advice you to change their names into single letters.