Crossword Puzzle Algebra problem

Clue: Algebra problem

Algebra problem, in a way (XYZAFFAIR with 9 letters)
Algebra problem directive (SOLVEFOR with 8 letters)
Frequent problem faced by algebra students (SOLVEFORX with 9 letters)
Answer to the algebra problem (XISTENANDYISSIX with 15 letters)
The rest of the algebra problem (XMINUSYISFOUR with 13 letters)
Admonition against trying algebra problems after imbibing? (DONTDRINKANDDERIVE with 18 letters)
Start of an algebra problem (XPLUSYISSIXTEEN with 15 letters)
Fix, as a printer paper problem (UNJAM with 5 letters)
Problem eater: Var. (BULIMIAC with 8 letters)
Problem drug (CRACK with 5 letters)