Question

What expression gives the discriminant of a quadratic equation \( ax^{2} + bx + c = 0 \)?

Options

• \[ D = b^{2} - 4ac \]

• \[ D = 2a - 4c \]

• \[ D = b^{2} + 4ac \]

• \[ D = b - 2ac \]

Answer 1

The discriminant of \( ax^{2} + bx + c = 0 \) is \( D = b^{2} - 4ac \). By checking the sign of \( D \), the nature of the roots can be identified without actually solving the equation.