Quadratic Solution Ddf043
1. **State the problem:** Solve the equation $$2(x + 1)(x - 4) - (x - 2)^2 = 0$$ for $x$.
2. **Expand and simplify:**
$$2(x + 1)(x - 4) = 2(x^2 - 4x + x - 4) = 2(x^2 - 3x - 4) = 2x^2 - 6x - 8$$
$$(x - 2)^2 = x^2 - 4x + 4$$
3. **Rewrite the equation:**
$$2x^2 - 6x - 8 - (x^2 - 4x + 4) = 0$$
4. **Simplify the left side:**
$$2x^2 - 6x - 8 - x^2 + 4x - 4 = 0$$
$$x^2 - 2x - 12 = 0$$
5. **Use the quadratic formula:**
For $ax^2 + bx + c = 0$, solutions are
$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
Here, $a=1$, $b=-2$, $c=-12$.
6. **Calculate discriminant:**
$$b^2 - 4ac = (-2)^2 - 4(1)(-12) = 4 + 48 = 52$$
7. **Write solutions:**
$$x = \frac{-(-2) \pm \sqrt{52}}{2(1)} = \frac{2 \pm \sqrt{52}}{2}$$
8. **Simplify square root:**
$$\sqrt{52} = \sqrt{4 \times 13} = 2\sqrt{13}$$
9. **Final solutions:**
$$x = \frac{2 \pm 2\sqrt{13}}{2} = 1 \pm \sqrt{13}$$
**Answer:**
$$x = 1 + \sqrt{13} \quad \text{or} \quad x = 1 - \sqrt{13}$$