1. **State the problem:** Solve the quadratic equation $3x^2 - 20x - 13 = -6$.
2. **Rewrite the equation:** Move all terms to one side to set the equation equal to zero:
$$3x^2 - 20x - 13 + 6 = 0$$
which simplifies to
$$3x^2 - 20x - 7 = 0$$
3. **Identify coefficients:** Here, $a = 3$, $b = -20$, and $c = -7$.
4. **Use the quadratic formula:**
$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
5. **Calculate the discriminant:**
$$b^2 - 4ac = (-20)^2 - 4 \times 3 \times (-7) = 400 + 84 = 484$$
6. **Find the square root of the discriminant:**
$$\sqrt{484} = 22$$
7. **Substitute values into the quadratic formula:**
$$x = \frac{-(-20) \pm 22}{2 \times 3} = \frac{20 \pm 22}{6}$$
8. **Calculate the two possible solutions:**
- For the plus sign:
$$x = \frac{20 + 22}{6} = \frac{42}{6} = 7$$
- For the minus sign:
$$x = \frac{20 - 22}{6} = \frac{\cancel{20 - 22}}{6} = \frac{-2}{6} = \frac{\cancel{-2}}{\cancel{6}} = -\frac{1}{3}$$
9. **Final answer:**
$$x = 7 \quad \text{or} \quad x = -\frac{1}{3}$$
Solve Quadratic 0E1813
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.