Modulus Equation 16Bdd0
1. **Problem:** Solve the equation $|x^2 - 14| = 5x$ for $x > 0$.
2. **Formula and approach:** Since the equation involves an absolute value, we consider two cases:
- Case 1: $x^2 - 14 = 5x$
- Case 2: $x^2 - 14 = -5x$
3. **Case 1:**
$$x^2 - 14 = 5x$$
Rearrange to standard quadratic form:
$$x^2 - 5x - 14 = 0$$
Use the quadratic formula $x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$ where $a=1$, $b=-5$, $c=-14$:
$$x = \frac{5 \pm \sqrt{(-5)^2 - 4 \times 1 \times (-14)}}{2} = \frac{5 \pm \sqrt{25 + 56}}{2} = \frac{5 \pm \sqrt{81}}{2}$$
$$x = \frac{5 \pm 9}{2}$$
Possible solutions:
- $x = \frac{5 + 9}{2} = 7$
- $x = \frac{5 - 9}{2} = -2$ (discard since $x > 0$)
4. **Case 2:**
$$x^2 - 14 = -5x$$
Rearranged:
$$x^2 + 5x - 14 = 0$$
Apply quadratic formula with $a=1$, $b=5$, $c=-14$:
$$x = \frac{-5 \pm \sqrt{5^2 - 4 \times 1 \times (-14)}}{2} = \frac{-5 \pm \sqrt{25 + 56}}{2} = \frac{-5 \pm \sqrt{81}}{2}$$
$$x = \frac{-5 \pm 9}{2}$$
Possible solutions:
- $x = \frac{-5 + 9}{2} = 2$
- $x = \frac{-5 - 9}{2} = -7$ (discard since $x > 0$)
5. **Final solutions for $x > 0$ are:**
$$x = 2 \text{ and } x = 7$$