1. **State the problem:** Find the square root of the complex number $8 - 6i$.
2. **Formula and approach:** To find the square root of a complex number $z = a + bi$, we look for $x + yi$ such that:
$$ (x + yi)^2 = a + bi $$
Expanding the left side:
$$ x^2 + 2xyi + (yi)^2 = x^2 - y^2 + 2xyi $$
Equate real and imaginary parts:
$$ x^2 - y^2 = a $$
$$ 2xy = b $$
3. **Apply to $8 - 6i$:**
$$ x^2 - y^2 = 8 $$
$$ 2xy = -6 $$
4. **Solve for $y$ from the second equation:**
$$ y = \frac{-6}{2x} = \frac{-3}{x} $$
5. **Substitute $y$ into the first equation:**
$$ x^2 - \left(\frac{-3}{x}\right)^2 = 8 $$
$$ x^2 - \frac{9}{x^2} = 8 $$
6. **Multiply both sides by $x^2$ to clear denominator:**
$$ \cancel{x^2} \left(x^2 - \frac{9}{x^2}\right) = 8 \cancel{x^2} $$
$$ x^4 - 9 = 8x^2 $$
7. **Rearrange to form a quadratic in $x^2$:**
$$ x^4 - 8x^2 - 9 = 0 $$
Let $u = x^2$, then:
$$ u^2 - 8u - 9 = 0 $$
8. **Solve quadratic equation:**
$$ u = \frac{8 \pm \sqrt{64 + 36}}{2} = \frac{8 \pm \sqrt{100}}{2} = \frac{8 \pm 10}{2} $$
9. **Two solutions for $u$:**
$$ u_1 = \frac{8 + 10}{2} = 9 $$
$$ u_2 = \frac{8 - 10}{2} = -1 $$
Since $u = x^2$, it must be non-negative, so $x^2 = 9$.
10. **Find $x$:**
$$ x = \pm 3 $$
11. **Find $y$ using $y = -3/x$:**
- If $x = 3$, then $y = -3/3 = -1$.
- If $x = -3$, then $y = -3/(-3) = 1$.
12. **Check the roots:**
$$ (3 - i)^2 = 9 - 6i + i^2 = 9 - 6i - 1 = 8 - 6i $$
$$ (-3 + i)^2 = 9 - 6i + i^2 = 9 - 6i - 1 = 8 - 6i $$
**Final answer:** The square roots of $8 - 6i$ are:
$$ 3 - i \quad \text{and} \quad -3 + i $$
Sqrt Complex 079D7F
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