1. **State the problem:** Solve the quadratic equation $-x^2 - 6x - 4 = 0$ for $x$.
2. **Rewrite the equation:** Multiply both sides by $-1$ to simplify the leading coefficient.
$$-1 \times (-x^2 - 6x - 4) = -1 \times 0$$
$$\cancel{-1} \times (-x^2) + \cancel{-1} \times (-6x) + \cancel{-1} \times (-4) = 0$$
$$x^2 + 6x + 4 = 0$$
3. **Use the quadratic formula:** For an equation $ax^2 + bx + c = 0$, the solutions are
$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
Here, $a=1$, $b=6$, and $c=4$.
4. **Calculate the discriminant:**
$$\Delta = b^2 - 4ac = 6^2 - 4 \times 1 \times 4 = 36 - 16 = 20$$
5. **Find the roots:**
$$x = \frac{-6 \pm \sqrt{20}}{2 \times 1} = \frac{-6 \pm \sqrt{20}}{2}$$
Simplify $\sqrt{20}$:
$$\sqrt{20} = \sqrt{4 \times 5} = 2\sqrt{5}$$
So,
$$x = \frac{-6 \pm 2\sqrt{5}}{2}$$
6. **Simplify the fraction:**
$$x = \frac{\cancel{2}(-3 \pm \sqrt{5})}{\cancel{2}} = -3 \pm \sqrt{5}$$
7. **Final answer:**
$$x_1 = -3 + \sqrt{5}, \quad x_2 = -3 - \sqrt{5}$$
Quadratic Solve 2E557F
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