1. **State the problem:** Solve the equation $$x |x - 8| = 24x + 4$$ for $x$ and identify which solutions are roots or extraneous.
2. **Understand the absolute value:** The expression $|x - 8|$ splits into two cases:
- Case 1: $x - 8 \geq 0 \Rightarrow |x - 8| = x - 8$
- Case 2: $x - 8 < 0 \Rightarrow |x - 8| = -(x - 8) = 8 - x$
3. **Solve Case 1 ($x \geq 8$):**
$$x |x - 8| = x(x - 8) = x^2 - 8x$$
Set equal to right side:
$$x^2 - 8x = 24x + 4$$
Bring all terms to one side:
$$x^2 - 8x - 24x - 4 = 0$$
$$x^2 - 32x - 4 = 0$$
Use quadratic formula:
$$x = \frac{32 \pm \sqrt{32^2 - 4 \cdot 1 \cdot (-4)}}{2} = \frac{32 \pm \sqrt{1024 + 16}}{2} = \frac{32 \pm \sqrt{1040}}{2}$$
Simplify $$\sqrt{1040} = \sqrt{16 \cdot 65} = 4\sqrt{65}$$:
$$x = \frac{32 \pm 4\sqrt{65}}{2} = 16 \pm 2\sqrt{65}$$
Check domain $x \geq 8$:
- $16 - 2\sqrt{65} \approx 16 - 16.12 = -0.12$ (not in domain)
- $16 + 2\sqrt{65} \approx 16 + 16.12 = 32.12$ (valid)
So from Case 1, valid root: $$x = 16 + 2\sqrt{65}$$
4. **Solve Case 2 ($x < 8$):**
$$x |x - 8| = x(8 - x) = 8x - x^2$$
Set equal to right side:
$$8x - x^2 = 24x + 4$$
Bring all terms to one side:
$$-x^2 + 8x - 24x - 4 = 0$$
$$-x^2 - 16x - 4 = 0$$
Multiply both sides by $-1$ to simplify:
$$\cancel{-}x^2 - 16x - 4 = 0 \Rightarrow \cancel{-}(-x^2 - 16x - 4) = 0 \Rightarrow x^2 + 16x + 4 = 0$$
Use quadratic formula:
$$x = \frac{-16 \pm \sqrt{16^2 - 4 \cdot 1 \cdot 4}}{2} = \frac{-16 \pm \sqrt{256 - 16}}{2} = \frac{-16 \pm \sqrt{240}}{2}$$
Simplify $$\sqrt{240} = \sqrt{16 \cdot 15} = 4\sqrt{15}$$:
$$x = \frac{-16 \pm 4\sqrt{15}}{2} = -8 \pm 2\sqrt{15}$$
Check domain $x < 8$:
- $-8 - 2\sqrt{15} \approx -8 - 7.75 = -15.75$ (valid)
- $-8 + 2\sqrt{15} \approx -8 + 7.75 = -0.25$ (valid)
So from Case 2, valid roots: $$x = -8 - 2\sqrt{15}, \quad x = -8 + 2\sqrt{15}$$
5. **Check all candidate solutions in original equation:**
- $x = -8 - 2\sqrt{15}$: Substitute and verify equality (true root).
- $x = -8 + 2\sqrt{15}$: Substitute and verify equality (true root).
- $x = 16 + 2\sqrt{65}$: Substitute and verify equality (true root).
- $x = 16 - 2\sqrt{65}$: Not in domain for Case 1, check substitution:
Substitute $x = 16 - 2\sqrt{65}$ into original:
Calculate $|x - 8| = |16 - 2\sqrt{65} - 8| = |8 - 2\sqrt{65}|$.
Since $2\sqrt{65} \approx 16.12$, $8 - 16.12 = -8.12$, absolute value is $8.12$.
Left side:
$$x |x - 8| = (16 - 2\sqrt{65}) \times 8.12$$
Right side:
$$24x + 4 = 24(16 - 2\sqrt{65}) + 4$$
Numerical approximation shows they are not equal, so extraneous.
6. **List roots in increasing order:**
$$-8 - 2\sqrt{15} < -8 + 2\sqrt{15} < 16 - 2\sqrt{65} < 16 + 2\sqrt{65}$$
7. **Label each:**
- $-8 - 2\sqrt{15}$: ROOT
- $-8 + 2\sqrt{15}$: ROOT
- $16 - 2\sqrt{65}$: EXTRANEOUS
- $16 + 2\sqrt{65}$: ROOT
**Final answer:**
$$\boxed{-8 - 2\sqrt{15} < -8 + 2\sqrt{15} < 16 - 2\sqrt{65} < 16 + 2\sqrt{65}}$$
with labels:
ROOT, ROOT, EXTRANEOUS, ROOT
Absolute Value Equation 5F7B30
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