Quadratic Equation 4A1571
1. **Problem:** Solve the quadratic equation $3x^2 - 5x - 9 = 0$ using the quadratic formula and give answers correct to 2 decimal places.
2. **Formula:** The quadratic formula is given by
$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
where $a$, $b$, and $c$ are coefficients from the quadratic equation $ax^2 + bx + c = 0$.
3. **Identify coefficients:** For $3x^2 - 5x - 9 = 0$, we have $a=3$, $b=-5$, and $c=-9$.
4. **Calculate the discriminant:**
$$\Delta = b^2 - 4ac = (-5)^2 - 4 \times 3 \times (-9) = 25 + 108 = 133$$
5. **Calculate the roots:**
$$x = \frac{-(-5) \pm \sqrt{133}}{2 \times 3} = \frac{5 \pm 11.53}{6}$$
6. **Find each solution:**
- First root:
$$x_1 = \frac{5 + 11.53}{6} = \frac{16.53}{6} = 2.76$$
- Second root:
$$x_2 = \frac{5 - 11.53}{6} = \frac{-6.53}{6} = -1.09$$
7. **Final answer:** The solutions to $3x^2 - 5x - 9 = 0$ are
$$x = 2.76 \text{ and } x = -1.09$$