Final answer:
The polynomial D) x⁶ - x⁴ - x² + 1 is the one in standard form because its terms are written in descending order of their exponents.
Step-by-step explanation:
The question pertains to identifying which polynomial is in standard form. A polynomial is in standard form when its terms are written in descending order of their exponents. Assessing the options provided:
- A) 5x⁷ - x¹ + 2x⁴ - x² is not in standard form because the terms are not in descending order.
- B) 9x⁸ - 4x² + 1 - x⁵ is not in standard form because the terms are not in descending order.
- C) 7x³ + 9x² - x² + 1 - x⁹ is not in standard form because the terms are not in descending order, and there's a term that should be combined (9x² - x²).
- D) x⁶ - x⁴ - x² + 1 is in standard form because the terms are written in descending order of their exponents.
Therefore, the polynomial in standard form is D) x⁶ - x⁴ - x² + 1.