1. **Problem statement:** Solve the equation $$x^2 = |2x + 4| + |x - 2|$$ for real values of $x$.
2. **Key idea:** Because of the absolute values, split the problem into intervals based on the points where the expressions inside the absolute values change sign.
These points are:
- $2x + 4 = 0 \Rightarrow x = -2$
- $x - 2 = 0 \Rightarrow x = 2$
So consider three intervals: $(-\infty, -2)$, $[-2, 2]$, and $(2, \infty)$.
3. **Interval 1: $x < -2$**
- $2x + 4 < 0$ so $|2x + 4| = -(2x + 4) = -2x - 4$
- $x - 2 < 0$ so $|x - 2| = -(x - 2) = -x + 2$
Equation becomes:
$$x^2 = (-2x - 4) + (-x + 2) = -3x - 2$$
Rewrite:
$$x^2 + 3x + 2 = 0$$
Factor:
$$(x + 1)(x + 2) = 0$$
Solutions:
$$x = -1, -2$$
Check domain $x < -2$:
- $x = -2$ is boundary, include it.
- $x = -1$ is not in $x < -2$, discard.
So valid solution here: $x = -2$.
4. **Interval 2: $-2 \leq x \leq 2$**
- $2x + 4 \geq 0$ so $|2x + 4| = 2x + 4$
- $x - 2 \leq 0$ so $|x - 2| = -(x - 2) = -x + 2$
Equation becomes:
$$x^2 = (2x + 4) + (-x + 2) = x + 6$$
Rewrite:
$$x^2 - x - 6 = 0$$
Factor:
$$(x - 3)(x + 2) = 0$$
Solutions:
$$x = 3, -2$$
Check domain $-2 \leq x \leq 2$:
- $x = -2$ valid
- $x = 3$ invalid
So valid solution here: $x = -2$ (already found).
5. **Interval 3: $x > 2$**
- $2x + 4 > 0$ so $|2x + 4| = 2x + 4$
- $x - 2 > 0$ so $|x - 2| = x - 2$
Equation becomes:
$$x^2 = (2x + 4) + (x - 2) = 3x + 2$$
Rewrite:
$$x^2 - 3x - 2 = 0$$
Use quadratic formula:
$$x = \frac{3 \pm \sqrt{9 + 8}}{2} = \frac{3 \pm \sqrt{17}}{2}$$
Approximate:
- $x_1 = \frac{3 + 4.123}{2} = 3.561$ (valid, since $> 2$)
- $x_2 = \frac{3 - 4.123}{2} = -0.561$ (invalid, since $\leq 2$)
So valid solution here: $x \approx 3.561$.
6. **Summary of solutions:**
- $x = -2$ (from intervals 1 and 2)
- $x \approx 3.561$ (from interval 3)
7. **Check solutions in original equation:**
- For $x = -2$:
$$LHS = (-2)^2 = 4$$
$$RHS = |2(-2) + 4| + |-2 - 2| = |0| + |-4| = 0 + 4 = 4$$
Valid.
- For $x \approx 3.561$:
$$LHS = (3.561)^2 \approx 12.68$$
$$RHS = |2(3.561) + 4| + |3.561 - 2| = |7.122 + 4| + |1.561| = 11.122 + 1.561 = 12.683$$
Close enough, valid.
**Your work had some sign and algebra errors, especially in handling the absolute values and quadratic formula steps.**
**Final correct solutions:**
$$x = -2, \quad x = \frac{3 + \sqrt{17}}{2}$$
Absolute Value Equation 1B84B1
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