Mathematics for IGCSE & O level - Equations (Section 3 - No. 46)
In the quadratic equation ax² + bx + c = 0, what does the sign of 'a' determine?
The number of solutions.
Whether the parabola opens upwards or downwards.
The vertex of the parabola.
The roots of the equation.
解释
If a > 0, the parabola opens up. If a < 0, the parabola opens down.