1. **State the problem:** Solve algebraically the equation $$\sqrt[2]{19a + 6} - 2a = 3$$.
2. **Rewrite the problem:** Since the index is 2, the radical is a square root. So the equation is $$\sqrt{19a + 6} - 2a = 3$$.
3. **Isolate the square root:** Add $2a$ to both sides:
$$\sqrt{19a + 6} = 3 + 2a$$
4. **Square both sides to eliminate the square root:**
$$\left(\sqrt{19a + 6}\right)^2 = (3 + 2a)^2$$
$$19a + 6 = (3 + 2a)^2$$
5. **Expand the right side:**
$$(3 + 2a)^2 = 3^2 + 2 \times 3 \times 2a + (2a)^2 = 9 + 12a + 4a^2$$
6. **Write the equation:**
$$19a + 6 = 9 + 12a + 4a^2$$
7. **Bring all terms to one side:**
$$0 = 9 + 12a + 4a^2 - 19a - 6$$
$$0 = 4a^2 + (12a - 19a) + (9 - 6)$$
$$0 = 4a^2 - 7a + 3$$
8. **Solve the quadratic equation:**
Use the quadratic formula:
$$a = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
where $a=4$, $b=-7$, $c=3$.
Calculate the discriminant:
$$\Delta = (-7)^2 - 4 \times 4 \times 3 = 49 - 48 = 1$$
Calculate the roots:
$$a = \frac{-(-7) \pm \sqrt{1}}{2 \times 4} = \frac{7 \pm 1}{8}$$
So,
$$a_1 = \frac{7 + 1}{8} = \frac{8}{8} = 1$$
$$a_2 = \frac{7 - 1}{8} = \frac{6}{8} = \frac{3}{4}$$
9. **Check for extraneous solutions:**
Substitute $a=1$ into the original equation:
$$\sqrt{19(1) + 6} - 2(1) = \sqrt{25} - 2 = 5 - 2 = 3$$ (True)
Substitute $a=\frac{3}{4}$:
$$\sqrt{19 \times \frac{3}{4} + 6} - 2 \times \frac{3}{4} = \sqrt{\frac{57}{4} + 6} - \frac{3}{2} = \sqrt{\frac{57}{4} + \frac{24}{4}} - \frac{3}{2} = \sqrt{\frac{81}{4}} - \frac{3}{2} = \frac{9}{2} - \frac{3}{2} = 3$$ (True)
Both solutions are valid.
**Final answer:** $$a = 1 \text{ or } a = \frac{3}{4}$$
Radical Equation 3D21Cc
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