Answer:
4x² - 9y²
General Formulas and Concepts:
Pre-Algebra
Algebra I
- Terms/Coefficients/Degrees
Step-by-step explanation:
Step 1: Define
Set up expression
12x² + 3xy - 5y² - (8x² + 3xy + 4y²)
Step 2: Simplify
- Distributive negative: 12x² + 3xy - 5y² - 8x² - 3xy - 4y²
- Combine like terms (x²): 4x² + 3xy - 5y² - 3xy - 4y²
- Combine like terms (xy): 4x² - 5y² - 4y²
- Combine like terms (y²): 4x² - 9y²