Answer:
5x^7 + 4x^4 - 2x^2 - 4x - 10
Step-by-step explanation:
(x^4-9x+5x^7)+(5x-10+3x^4-2x^2) = 4x^4 - 9x + 5x^7 + 5x - 10 - 2x^2
= 4x^4 - 9x + 5x^7 + 5x - 10 - 2x^2
= 4x^4 - 4x + 5x^7 - 10 - 2x^2
= 5x^7 + 4x^4 - 2x^2 - 4x - 10
