Answer:
9x² - 9y + 9
Step-by-step explanation:
Step 1: Write out expression
3 - 2y - 1 + 5x² - 7y + 7 + 4x²
Step 2: Combine like terms (x²)
9x² + 3 - 2y - 1 - 7y + 7
Step 3: Combine like terms (y)
9x² - 9y + 3 - 1 + 7
Step 4: Combine like terms (constants)
9x² - 9y + 9
