Unsolvable \Unsolvable\ See solvable.

Source: The Collaborative International Dictionary of English v.0.48
 

unsolvable adj : not easily solved; "an apparantly insolvable problem"; "public finance...had long presented problems unsolvable or at least unsolved"- C.L.Jones [syn: insolvable, unsoluble, unresolvable]

Source: WordNet (r) 2.0