1. **State the problem:** Solve the polynomial equation $$x^4 + 6x^3 - 33x^2 - 46x + 72 = 0$$ for all roots.
2. **Use the Rational Root Theorem:** Possible rational roots are factors of 72 divided by factors of 1, i.e., $$\pm1, \pm2, \pm3, \pm4, \pm6, \pm8, \pm9, \pm12, \pm18, \pm24, \pm36, \pm72$$.
3. **Test possible roots:** Substitute values to find roots.
- Test $x=2$:
$$2^4 + 6(2)^3 - 33(2)^2 - 46(2) + 72 = 16 + 48 - 132 - 92 + 72 = -88 \neq 0$$
- Test $x=3$:
$$3^4 + 6(3)^3 - 33(3)^2 - 46(3) + 72 = 81 + 162 - 297 - 138 + 72 = -120 \neq 0$$
- Test $x=1$:
$$1 + 6 - 33 - 46 + 72 = 0$$ so $x=1$ is a root.
4. **Divide polynomial by $(x-1)$:**
Use synthetic division:
Coefficients: 1, 6, -33, -46, 72
Bring down 1.
Multiply 1 by 1, add to 6: 7.
Multiply 7 by 1, add to -33: -26.
Multiply -26 by 1, add to -46: -72.
Multiply -72 by 1, add to 72: 0.
Quotient polynomial: $$x^3 + 7x^2 - 26x - 72$$
5. **Factor cubic:** Try rational roots again.
Test $x=2$:
$$8 + 28 - 52 - 72 = -88 \neq 0$$
Test $x=3$:
$$27 + 63 - 78 - 72 = -60 \neq 0$$
Test $x=4$:
$$64 + 112 - 104 - 72 = 0$$ so $x=4$ is a root.
6. **Divide cubic by $(x-4)$:**
Coefficients: 1, 7, -26, -72
Bring down 1.
Multiply 1 by 4, add to 7: 11.
Multiply 11 by 4, add to -26: 18.
Multiply 18 by 4, add to -72: 0.
Quotient polynomial: $$x^2 + 11x + 18$$
7. **Factor quadratic:**
$$x^2 + 11x + 18 = (x + 9)(x + 2)$$
8. **Roots:**
$$x = 1, 4, -9, -2$$
9. **Order roots from smallest to largest:**
$$x = -9, -2, 1, 4$$
**Final answer:** $$\boxed{-9, -2, 1, 4}$$
Polynomial Roots D658E6
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