Answer:
Step-by-step explanation:
to find what you need to add, ur gonna have to subtract.....subtract the second polynomial from the first one
but lets rearrange the second one
4x^4 - x^3 + 3x^2 + 3...thats better
now, we subract
3x^4 - 9x^3 + 5x^2 - x + 7 - (4x^4 - x^3 + 3x^2 + 3) =
3x^4 - 9x^3 + 5x^2 - x + 7 - 4x^4 + x^3 - 3x^2 - 3) =
-x^4 - 8x^3 + 2x^2 - x + 4 <=== ur answer
