1. Stating the problem:
Solve the equation involving absolute values: $$|2x - 1| = 3 |x + 1|$$
2. Understanding the absolute value equation:
Absolute value expressions can split into cases depending on whether the inside is positive or negative.
3. Setting up cases:
Case 1: Both inside expressions are non-negative or both negative such that the equality holds as is.
Case 2: One expression is negative and the other positive, which flips the sign accordingly.
4. Identify critical points where expressions inside absolute values change sign:
- For $$2x - 1$$, zero at $$x = \frac{1}{2}$$.
- For $$x + 1$$, zero at $$x = -1$$.
5. We split the real line into intervals:
- $$(-\infty, -1)$$,
- $$[-1, \frac{1}{2})$$,
- $$[\frac{1}{2}, \infty)$$.
6. Case analysis:
- Interval 1: $$x < -1$$
Here $$2x-1 < 0$$ and $$x+1 < 0$$.
So $$|2x-1| = -(2x-1) = -2x + 1$$ and $$|x+1| = -(x+1) = -x -1$$.
Substitute:
$$-2x + 1 = 3(-x - 1)$$
Simplify:
$$-2x + 1 = -3x -3$$
$$-2x + 1 + 3x + 3 = 0$$
$$x + 4 = 0$$
$$x = -4$$
Check if in interval: $$-4 < -1$$ is true, so $$x = -4$$ is valid.
- Interval 2: $$-1 \leq x < \frac{1}{2}$$
Here $$2x -1 < 0$$ but $$x + 1 \geq 0$$.
So $$|2x -1| = -2x + 1$$ and $$|x +1| = x +1$$.
Substitute:
$$-2x + 1 = 3(x + 1)$$
Simplify:
$$-2x + 1 = 3x + 3$$
$$-2x +1 - 3x -3 = 0$$
$$-5x - 2 = 0$$
$$-5x = 2$$
$$x = -\frac{2}{5}$$
Check if in interval: $$-1 \leq -\frac{2}{5} < \frac{1}{2}$$ is true, so $$x = -\frac{2}{5}$$ is valid.
- Interval 3: $$x \geq \frac{1}{2}$$
Here $$2x -1 \geq 0$$ and $$x+1 \geq 0$$.
So $$|2x -1| = 2x -1$$ and $$|x +1| = x +1$$.
Substitute:
$$2x -1 = 3(x +1)$$
Simplify:
$$2x -1 = 3x + 3$$
$$2x -1 - 3x -3 = 0$$
$$-x - 4 = 0$$
$$-x =4$$
$$x = -4$$
Check if in interval: $$x \geq \frac{1}{2}$$ but $$-4 \not\geq \frac{1}{2}$$.
So no solution here.
7. Final solutions are $$x = -4$$ and $$x = -\frac{2}{5}$$.
Answer: $$\boxed{x = -4, -\frac{2}{5}}$$
Abs Value Eq
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