Answer:
5x^7 + 4x^4 - 2x^2 - 4x - 10.
Step-by-step explanation:
(x^4 - 9x + 5x^7) + (5x - 10 + 3x^4 - 2x^2)
= x^4 - 9x + 5x^7 + 5x - 10 + 3x^4 - 2x^2
Combine like terms:
= 4x^4 - 4x - 2x^2 + 5x^7 - 10
Now rearrange to standard form ( in decreasing degree):
= 5x^7 + 4x^4 - 2x^2 - 4x - 10.
