1. **State the problem:** Find the roots of the cubic function $$f(x) = x^3 - 2x^2 + 4x - 8$$ and express it in intercept form.
2. **Number of roots:** A cubic polynomial has exactly 3 roots (real or complex) according to the Fundamental Theorem of Algebra.
3. **Find rational roots using the Rational Root Theorem:** Possible rational roots are factors of the constant term 8 divided by factors of the leading coefficient 1, i.e., $$\pm1, \pm2, \pm4, \pm8$$.
4. **Test rational roots by substitution:**
- Test $$x=2$$:
$$f(2) = 2^3 - 2(2)^2 + 4(2) - 8 = 8 - 8 + 8 - 8 = 0$$
So, $$x=2$$ is a root.
5. **Divide the polynomial by $$x-2$$ to find the quadratic factor:**
Using synthetic division:
$$\begin{array}{r|rrrr}
2 & 1 & -2 & 4 & -8 \\
& & 2 & 0 & 8 \\
\hline
& 1 & 0 & 4 & 0 \\
\end{array}$$
The quotient is $$x^2 + 0x + 4 = x^2 + 4$$.
6. **Find roots of the quadratic factor:**
Solve $$x^2 + 4 = 0$$
$$x^2 = -4$$
$$x = \pm \sqrt{-4} = \pm 2i$$
These are complex roots.
7. **Summary of roots:**
- Rational root: $$x=2$$
- Complex roots: $$x=2i$$ and $$x=-2i$$
8. **Write the intercept form:**
$$f(x) = (x - 2)(x - 2i)(x + 2i)$$
Since $$(x - 2i)(x + 2i) = x^2 + 4$$,
$$f(x) = (x - 2)(x^2 + 4)$$
**Final answers:**
- Rational Roots: $$x=2$$
- Complex or Irrational Roots: $$x=\pm 2i$$
- Intercept Form: $$f(x) = (x - 2)(x^2 + 4)$$
Complex Irrational Roots 970A7F
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