Expanding the expression, we get:
2(3a² - b²) - (3a - 2b)(2a + b)= 6a² - 2b² - (6a² + 3ab - 4ab - 2b²)= 6a² - 2b² - 6a² - 3ab + 4ab + 2b²= -3ab + 2b²
Therefore, the simplified expression is -3ab + 2b².
Expanding the expression, we get:
2(3a² - b²) - (3a - 2b)(2a + b)
= 6a² - 2b² - (6a² + 3ab - 4ab - 2b²)
= 6a² - 2b² - 6a² - 3ab + 4ab + 2b²
= -3ab + 2b²
Therefore, the simplified expression is -3ab + 2b².