Try another version of this question Box 1: Enter your answer as an expression. Example: 3x^2+1, x/5, (a+b)/c
Add the 2 polynomials:
`(-2x^4+9x^3-8x) + (x^4+6x^3-9)`
Be sure your variables match those in the question `-x^4+15x^3-8x-9`