Final answer:
The difference of the given polynomials is 7x² + 3y² - 4x.
Step-by-step explanation:
To find the difference between two polynomials, we need to subtract the second polynomial from the first polynomial (12x² – 11y² - 13x) - (5x² – 14y² – 9x)
We can remove the brackets and then rearrange the terms:
12x² - 11y² - 13x - 5x² + 14y² + 9x
Combining like terms, we have:
7x² + 3y² - 4x