1. **State the problem:** Solve the equation $-18 = 2a - 2|1 - 3a|$ for $a$.
2. **Understand the absolute value:** The absolute value expression $|1 - 3a|$ splits the problem into two cases:
- Case 1: $1 - 3a \geq 0 \Rightarrow a \leq \frac{1}{3}$
- Case 2: $1 - 3a < 0 \Rightarrow a > \frac{1}{3}$
3. **Case 1: $a \leq \frac{1}{3}$**
Replace $|1 - 3a|$ with $(1 - 3a)$:
$$-18 = 2a - 2(1 - 3a)$$
Simplify:
$$-18 = 2a - 2 + 6a$$
$$-18 = 8a - 2$$
Add 2 to both sides:
$$-18 + 2 = 8a$$
$$-16 = 8a$$
Divide both sides by 8:
$$\cancel{8}a = \frac{-16}{\cancel{8}}$$
$$a = -2$$
Check if $a = -2$ satisfies $a \leq \frac{1}{3}$:
Yes, since $-2 \leq \frac{1}{3}$.
4. **Case 2: $a > \frac{1}{3}$**
Replace $|1 - 3a|$ with $-(1 - 3a) = 3a - 1$:
$$-18 = 2a - 2(3a - 1)$$
Simplify:
$$-18 = 2a - 6a + 2$$
$$-18 = -4a + 2$$
Subtract 2 from both sides:
$$-18 - 2 = -4a$$
$$-20 = -4a$$
Divide both sides by $-4$:
$$\cancel{-4}a = \frac{-20}{\cancel{-4}}$$
$$a = 5$$
Check if $a = 5$ satisfies $a > \frac{1}{3}$:
Yes, since $5 > \frac{1}{3}$.
5. **Final solution:** The solutions are $a = -2$ and $a = 5$.
6. **Answer set:** $\{-2, 5\}$ which corresponds to option D.
Absolute Value Equation Fe5731
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