Posted by DK on Monday, March 8, 2010 at 6:20pm.
Factor by introducing an appropriate substitution.
5y10  31y5  28

Math  Reiny, Monday, March 8, 2010 at 6:39pm
You must have meant to type
5y^10  31y^5  28
then ... let y^5 = x
5x^  31x  28
= (x7)(5x + 4)
= (y^5  7)(5y^5 + 4)