Answer:
[tex]-8x^4 + 6x^3 + 12x^2 + 5x -9[/tex]
Step-by-step explanation:
To write a polynomial in standard form, list its terms from highest to lowest degree. The degree of a term is represented by its exponents. Thus, rearrange the terms so that the terms with the highest exponents are first and the ones with the lowest are last.
[tex]6x^3-8x^4+5x+12x^2-9\\-8x^4 + 6x^3 + 12x^2 + 5x -9[/tex]
Thus, [tex]-8x^4 + 6x^3 + 12x^2 + 5x -9[/tex] is the answer.
