1. The problem is to analyze and graph the quadratic function $f(x) = 3x^2 + 3x - 6$.
2. The general form of a quadratic function is $f(x) = ax^2 + bx + c$, where $a$, $b$, and $c$ are constants.
3. For this function, $a=3$, $b=3$, and $c=-6$.
4. To find the vertex, use the formula for the x-coordinate of the vertex: $$x = -\frac{b}{2a} = -\frac{3}{2 \times 3} = -\frac{3}{6} = -\frac{1}{2}.$$
5. Substitute $x = -\frac{1}{2}$ into $f(x)$ to find the y-coordinate of the vertex:
$$f\left(-\frac{1}{2}\right) = 3\left(-\frac{1}{2}\right)^2 + 3\left(-\frac{1}{2}\right) - 6 = 3\times \frac{1}{4} - \frac{3}{2} - 6 = \frac{3}{4} - \frac{3}{2} - 6.$$
6. Simplify the y-coordinate:
$$\frac{3}{4} - \frac{3}{2} - 6 = \frac{3}{4} - \frac{6}{4} - \frac{24}{4} = \frac{3 - 6 - 24}{4} = \frac{-27}{4} = -6.75.$$
7. The vertex is at $$\left(-\frac{1}{2}, -6.75\right).$$
8. The parabola opens upwards because $a=3 > 0$.
9. To find the y-intercept, set $x=0$:
$$f(0) = -6.$$
10. To find the x-intercepts, solve $3x^2 + 3x - 6 = 0$:
Divide both sides by 3:
$$\cancel{3}x^2 + \cancel{3}x - \cancel{6} = 0 \Rightarrow x^2 + x - 2 = 0.$$
11. Factor the quadratic:
$$(x + 2)(x - 1) = 0.$$
12. So, the solutions are:
$$x = -2 \quad \text{or} \quad x = 1.$$
13. The x-intercepts are at $(-2, 0)$ and $(1, 0)$.
14. Summary:
- Vertex: $\left(-\frac{1}{2}, -6.75\right)$
- Opens upward
- Y-intercept: $(0, -6)$
- X-intercepts: $(-2, 0)$ and $(1, 0)$
This information can be used to sketch the graph of the function.
Quadratic Graph C5Ec79
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