1. **Stating the problem:** Solve the cubic equation $$3x^3 - 26x^2 + 52x - 24 = 0$$ given that the roots are in geometric progression.
2. **Let the roots be:** $$a, ar, ar^2$$ where $$a$$ is the first root and $$r$$ is the common ratio.
3. **Sum of roots:** By Viète's formulas for cubic equations $$ax^3 + bx^2 + cx + d = 0$$ with roots $$
ho_1,
ho_2,
ho_3$$,
$$
ho_1 +
ho_2 +
ho_3 = -\frac{b}{a}$$
For our equation, $$a=3, b=-26$$, so
$$a + ar + ar^2 = \frac{26}{3}$$
Factor out $$a$$:
$$a(1 + r + r^2) = \frac{26}{3}$$
4. **Sum of products of roots taken two at a time:**
$$
ho_1\rho_2 + \rho_2\rho_3 + \rho_3\rho_1 = \frac{c}{a}$$
Here, $$c=52$$, so
$$a^2(r + r^2 + r^3) = \frac{52}{3}$$
Note that $$r + r^2 + r^3 = r(1 + r + r^2)$$, so
$$a^2 r (1 + r + r^2) = \frac{52}{3}$$
5. **Product of roots:**
$$
ho_1 \rho_2 \rho_3 = -\frac{d}{a}$$
Here, $$d = -24$$, so
$$a^3 r^3 = \frac{24}{3} = 8$$
6. **From step 3:**
$$a = \frac{26}{3(1 + r + r^2)}$$
7. **Substitute $$a$$ into step 5:**
$$\left(\frac{26}{3(1 + r + r^2)}\right)^3 r^3 = 8$$
Simplify:
$$\frac{26^3 r^3}{27 (1 + r + r^2)^3} = 8$$
Multiply both sides by denominator:
$$26^3 r^3 = 8 \times 27 (1 + r + r^2)^3$$
Calculate constants:
$$26^3 = 17576$$
$$8 \times 27 = 216$$
So:
$$17576 r^3 = 216 (1 + r + r^2)^3$$
8. **Take cube root of both sides:**
$$\sqrt[3]{17576} r = \sqrt[3]{216} (1 + r + r^2)$$
Since $$\sqrt[3]{17576} = 26$$ and $$\sqrt[3]{216} = 6$$,
$$26 r = 6 (1 + r + r^2)$$
9. **Rewrite:**
$$26 r = 6 + 6 r + 6 r^2$$
Bring all terms to one side:
$$6 r^2 + 6 r + 6 - 26 r = 0$$
Simplify:
$$6 r^2 - 20 r + 6 = 0$$
Divide entire equation by 2:
$$3 r^2 - 10 r + 3 = 0$$
10. **Solve quadratic for $$r$$:**
$$r = \frac{10 \pm \sqrt{(-10)^2 - 4 \times 3 \times 3}}{2 \times 3} = \frac{10 \pm \sqrt{100 - 36}}{6} = \frac{10 \pm \sqrt{64}}{6}$$
$$r = \frac{10 \pm 8}{6}$$
So,
$$r_1 = \frac{18}{6} = 3$$
$$r_2 = \frac{2}{6} = \frac{1}{3}$$
11. **Find corresponding $$a$$ for each $$r$$ using step 3:**
For $$r=3$$:
$$a = \frac{26}{3(1 + 3 + 9)} = \frac{26}{3 \times 13} = \frac{26}{39} = \frac{2}{3}$$
For $$r=\frac{1}{3}$$:
$$a = \frac{26}{3(1 + \frac{1}{3} + \frac{1}{9})} = \frac{26}{3 \times \frac{13}{9}} = \frac{26}{\frac{39}{9}} = \frac{26 \times 9}{39} = 6$$
12. **Roots for each case:**
- For $$r=3$$:
$$a = \frac{2}{3}$$
Roots: $$\frac{2}{3}, 2, 6$$
- For $$r=\frac{1}{3}$$:
$$a = 6$$
Roots: $$6, 2, \frac{2}{3}$$
Both sets are the same roots in different order.
13. **Verify roots satisfy the original equation:**
The roots are $$\frac{2}{3}, 2, 6$$.
14. **Final answer:**
The roots of the equation $$3x^3 - 26x^2 + 52x - 24 = 0$$ with roots in geometric progression are $$\boxed{\frac{2}{3}, 2, 6}$$.
Geometric Roots
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