Final answer:
The sum of the polynomials (7x² - 4x²) + (2x² - 4x²) is x².
Step-by-step explanation:
To find the sum of the polynomials (7x² - 4x²) + (2x² - 4x²), we can combine like terms. The terms 7x² and 2x² are like terms because they both have the same exponent, so we can add them together. Similarly, the terms -4x² and -4x² are like terms, so we can add them together as well. Adding the like terms, we get:
(7x² - 4x²) + (2x² - 4x²) = 7x² + 2x² - 4x² - 4x²
Combining like terms again, we get:
7x² + 2x² - 4x² - 4x² = (7 + 2 - 4 - 4)x² = 1x² = x²