Quadratic Formula
1. The problem involves finding the discriminant $\Delta$ and the roots $x_1$ and $x_2$ of a quadratic equation of the form $ax^2 + bx + c = 0$.
2. The formula for the discriminant is:
$$\Delta = b^2 - 4ac$$
This helps determine the nature of the roots.
3. The roots are given by the quadratic formula:
$$x_1 = \frac{-b + \sqrt{\Delta}}{2a}$$
$$x_2 = \frac{-b - \sqrt{\Delta}}{2a}$$
These are the two solutions where the parabola intersects the x-axis.
4. The graph is a parabola opening upwards, intersecting the x-axis near $(-1, 0)$ and $(4, 0)$, and the y-axis near $(0, -5)$.
5. The vertex is near $(1.5, -7)$, confirming that $a > 0$ (parabola opens upwards) and the minimum value is at the vertex.
6. Based on the given points, approximating the quadratic equation could be:
Using vertex form:
$$y = a(x - h)^2 + k$$
where vertex $(h, k) = (1.5, -7)$.
Using the y-intercept $(0, -5)$:
$$-5 = a(0 - 1.5)^2 - 7$$
$$-5 + 7 = a(2.25)$$
$$2 = 2.25a$$
$$a = \frac{2}{2.25} = \frac{8}{9} \approx 0.89$$
7. The approximate quadratic equation then is:
$$y = \frac{8}{9}(x - 1.5)^2 - 7$$
8. This aligns with the graph and x-intercepts near $-1$ and $4$.
Final answer:
$$\Delta = b^2 - 4ac$$
$$x_1 = \frac{-b + \sqrt{\Delta}}{2a}$$
$$x_2 = \frac{-b - \sqrt{\Delta}}{2a}$$
and the approximate quadratic function based on the graph is:
$$y = \frac{8}{9}(x - 1.5)^2 - 7$$