Final Answer:
The solution is -18x⁴ + 64x³ + 7x² - x + 20.
Step-by-step explanation:
To multiply the polynomials (2x² - 6x - 5) and (-9x² + 5x - 4), we can use the distributive property.
Steps to solve:
Distribute the first polynomial: -18x⁴ + 10x³ - 8x² - 6x(-9x² + 5x - 4) - 5(-9x² + 5x - 4)
Distribute the second polynomial: -18x⁴ + 10x³ - 8x² + 54x³ - 30x² + 24x - 5(-9x² + 5x - 4)
Distribute the third polynomial: -18x⁴ + 10x³ - 8x² + 54x³ - 30x² + 24x + 45x² - 25x + 20
Combine like terms: -18x⁴ + 64x³ - 8x² + 7x² + 24x - 25x + 20
Combine like terms: -18x⁴ + 64x³ + 7x² - x + 20
Answer is: -18x⁴ + 64x³ + 7x² - x + 20