Question 83280
(5x^5-5x^4-3x^3-5)-(9x^5-3x^4+7x^3-7)
-----------
Comment: You can only add or subtract "like" terms:
=(5x^5-9x^5)+(-5x^4+3x^4)+(-3x^3-7x^3)+(-5+7)

= -4x^5 -2x^4 -10x^3 +2
==============
Cheers,
Stan H.