1. **State the problem:** Solve the quadratic equation $x^2 - 2x = 8$ for $x$.
2. **Rewrite the equation:** Move all terms to one side to set the equation equal to zero:
$$x^2 - 2x - 8 = 0$$
3. **Identify the quadratic formula:** For an equation $ax^2 + bx + c = 0$, the solutions are given by:
$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
where $a=1$, $b=-2$, and $c=-8$.
4. **Calculate the discriminant:**
$$\Delta = b^2 - 4ac = (-2)^2 - 4(1)(-8) = 4 + 32 = 36$$
5. **Find the square root of the discriminant:**
$$\sqrt{36} = 6$$
6. **Apply the quadratic formula:**
$$x = \frac{-(-2) \pm 6}{2(1)} = \frac{2 \pm 6}{2}$$
7. **Calculate the two solutions:**
- For the plus sign:
$$x = \frac{2 + 6}{2} = \frac{8}{2} = 4$$
- For the minus sign:
$$x = \frac{2 - 6}{2} = \frac{\cancel{2} - 6}{\cancel{2}} = \frac{-4}{2} = -2$$
8. **Final answer:** The solutions to the equation are:
$$x = 4 \quad \text{or} \quad x = -2$$
Quadratic Solve 814Fde
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.