Which of the following is a quadratic equation?

1. x² + 1 = (2 - x)² + 3

2. 2x² + 3 = (5 + x)(2x - 3)

3. x³ - x² = (x - 1)³

4. none of these

Which of the following quadratic equations has 2 and 3 as its roots?

1. x² - 5x + 6 = 0

2. x² + 5x + 6 = 0

3. x² - 5x - 6 = 0

4. x² + 5x - 6 = 0