1. **State the problem:** Solve the equation $$\sqrt{2x+2} = -2 + \sqrt{6x-6}$$.
2. **Important note:** The square root function $$\sqrt{y}$$ is defined only for $$y \geq 0$$ and always returns a non-negative value. Therefore, the left side $$\sqrt{2x+2} \geq 0$$. The right side is $$-2 + \sqrt{6x-6}$$, which must also be non-negative for equality to hold.
3. **Check domain restrictions:**
- For $$\sqrt{2x+2}$$, require $$2x+2 \geq 0 \Rightarrow x \geq -1$$.
- For $$\sqrt{6x-6}$$, require $$6x-6 \geq 0 \Rightarrow x \geq 1$$.
So the domain is $$x \geq 1$$.
4. **Analyze the right side:** Since $$\sqrt{6x-6} \geq 0$$, then $$-2 + \sqrt{6x-6} \geq -2$$. For the right side to be non-negative, we need:
$$-2 + \sqrt{6x-6} \geq 0 \Rightarrow \sqrt{6x-6} \geq 2$$
Square both sides:
$$6x - 6 \geq 4 \Rightarrow 6x \geq 10 \Rightarrow x \geq \frac{10}{6} = \frac{5}{3} \approx 1.666...$$
5. **Update domain:** $$x \geq \frac{5}{3}$$.
6. **Isolate the square roots:**
$$\sqrt{2x+2} + 2 = \sqrt{6x-6}$$
7. **Square both sides:**
$$\left(\sqrt{2x+2} + 2\right)^2 = (\sqrt{6x-6})^2$$
$$ (\sqrt{2x+2})^2 + 2 \times 2 \times \sqrt{2x+2} + 2^2 = 6x - 6$$
$$ 2x + 2 + 4\sqrt{2x+2} + 4 = 6x - 6$$
8. **Simplify:**
$$ 2x + 6 + 4\sqrt{2x+2} = 6x - 6$$
9. **Isolate the square root term:**
$$4\sqrt{2x+2} = 6x - 6 - 2x - 6 = 4x - 12$$
10. **Divide both sides by 4:**
$$\cancel{4}\sqrt{2x+2} = \cancel{4}(x - 3) \Rightarrow \sqrt{2x+2} = x - 3$$
11. **Since $$\sqrt{2x+2} \geq 0$$, we require $$x - 3 \geq 0 \Rightarrow x \geq 3$$**.
12. **Square both sides again:**
$$ (\sqrt{2x+2})^2 = (x - 3)^2$$
$$ 2x + 2 = (x - 3)^2 = x^2 - 6x + 9$$
13. **Bring all terms to one side:**
$$ 0 = x^2 - 6x + 9 - 2x - 2 = x^2 - 8x + 7$$
14. **Solve quadratic equation:**
$$x^2 - 8x + 7 = 0$$
Use quadratic formula:
$$x = \frac{8 \pm \sqrt{64 - 28}}{2} = \frac{8 \pm \sqrt{36}}{2} = \frac{8 \pm 6}{2}$$
15. **Calculate roots:**
- $$x = \frac{8 + 6}{2} = 7$$
- $$x = \frac{8 - 6}{2} = 1$$
16. **Check domain and original equation:**
- $$x=1$$ is less than 3, so discard.
- $$x=7$$ satisfies $$x \geq 3$$.
17. **Verify $$x=7$$ in original equation:**
Left side:
$$\sqrt{2(7)+2} = \sqrt{14 + 2} = \sqrt{16} = 4$$
Right side:
$$-2 + \sqrt{6(7) - 6} = -2 + \sqrt{42 - 6} = -2 + \sqrt{36} = -2 + 6 = 4$$
Both sides equal 4, so $$x=7$$ is a valid solution.
**Final answer:** $$\boxed{7}$$
Sqrt Equation 5D0246
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