解とけない

i-adjective

unsolvable; insoluble

Describes a problem, puzzle, or mystery that cannot be solved or resolved. Often used for abstract difficulties.

• この問もん題だいは難むずかしすぎて、私わたしには解とけない。

  This problem is too difficult for me to solve.

• その謎なぞは永えい遠えんに解とけないかもしれない。

  That mystery may never be solved.