【Solve】 , 【resolve】 , 【unfold】 , 【unravel】 , 【decipher】 can all mean to make clear or apparent or intelligible what is obscure or mysterious or incomprehensible.
【Solve】 is the most general in meaning and suggestion in this group; it implies the finding of a satisfactory answer or solution, usually to something of at least moderate difficulty.
【Resolve】 (see also ANALYZE ), as contrasted with 【solve】 , is likely to indicate analytic arrangement and consideration of the various phases or items of a problem or situation rather than finding a final solution or answer and is likely to suggest dispelling of confusion or perplexity by a clear formulation of questions or issues.
In some situations this process may achieve an answer, especially a ready or summary one.
【Unfold】 implies continuous opening up, clarifying, and making more and more clear and patent until a full solution or resolution is apparent.
【Unravel】 stresses the notion of making a clear and orderly rearrangement of something entangled or a simple ordering of something complicated, especially by patient endeavor.
【Decipher】 stresses the notion of finding the meaning or significance of something very obscure, clouded, cryptic, or enigmatic.