The answer key for each practice sheet is on the last page(s) of each practice sheet.
Add/Subtract Polynomials
Practice (Add): http://jmap.org/Worksheets/A.APR.A.1.OperationswithPolynomials1a.pdf
Practice (Subtract): http://jmap.org/Worksheets/A.APR.A.1.OperationswithPolynomials2a.pdf
Multiply Polynomials
Factoring (Greatest Common Factor)
Factoring (Difference of Two Squares)
Factoring (Trinomials)
Factoring (Trinomials - Leading Coefficient is Greater than 1):
Factoring Completely