so, like this, in this way

difficult / hard, probably impossible

be solved / be solvable / be soluble / be untied, be undone / melt, thaw (ice, snow, etc.) / to melt away, to be dispelled (anger, misunderstanding, etc.)

be untied, be undone

phooey

(～と)

question, problem on homework etc. / a question; a matter (of time etc.) / a problem (something that needs to be dealt with); a trouble / an issue; a matter

(informal) no problem

unthinkable, out of the question

practical question (problem)