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.
Giải thích
If a > 0, the parabola opens up. If a < 0, the parabola opens down.