1. **State the problem:** Solve the equation $$2x^4 + 6x^2 - 8 = 0$$ for $x$.
2. **Use substitution:** Let $y = x^2$. Then the equation becomes $$2y^2 + 6y - 8 = 0$$.
3. **Simplify the quadratic equation:** Divide the entire equation by 2 to make it simpler:
$$y^2 + 3y - 4 = 0$$.
4. **Factor the quadratic:** Find two numbers that multiply to $-4$ and add to $3$. These are $4$ and $-1$.
$$y^2 + 4y - y - 4 = 0$$
$$(y + 4)(y - 1) = 0$$.
5. **Solve for $y$:** Set each factor equal to zero:
$$y + 4 = 0 \Rightarrow y = -4$$
$$y - 1 = 0 \Rightarrow y = 1$$.
6. **Recall substitution:** Since $y = x^2$, solve for $x$:
- For $y = -4$, $x^2 = -4$ has no real solutions because the square of a real number cannot be negative.
- For $y = 1$, $x^2 = 1$ gives $x = \pm 1$.
7. **Final answer:** The real solutions are $$x = \pm 1$$.
**Note:** The solutions $x = \pm \sqrt{-4}$ are complex and not real numbers.
Solve Quartic
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