1. **State the problem:** Solve the equation $$\sqrt{2k+3} = k+2$$ and determine which of the statements I, II, and III are true.
2. **Solve the equation:**
Square both sides to eliminate the square root:
$$\left(\sqrt{2k+3}\right)^2 = (k+2)^2$$
$$2k + 3 = (k+2)^2$$
Expand the right side:
$$2k + 3 = k^2 + 4k + 4$$
Bring all terms to one side:
$$0 = k^2 + 4k + 4 - 2k - 3$$
$$0 = k^2 + 2k + 1$$
This factors as:
$$(k + 1)^2 = 0$$
So,
$$k = -1$$
3. **Check for extraneous solutions:**
Substitute $k = -1$ back into the original equation:
$$\sqrt{2(-1) + 3} = \sqrt{1} = 1$$
$$k + 2 = -1 + 2 = 1$$
Both sides equal 1, so $k = -1$ is a valid solution.
4. **Evaluate the statements:**
- I. $$k^k = k$$
Calculate:
$$(-1)^{-1} = \frac{1}{-1} = -1$$
Right side:
$$k = -1$$
So, $$(-1)^{-1} = -1$$ is true.
- II. $$|k| = -k$$
Calculate:
$$| -1 | = 1$$
$$-k = -(-1) = 1$$
So, $$|k| = -k$$ is true.
- III. $$k^0 = -k$$
Calculate:
$$k^0 = (-1)^0 = 1$$
$$-k = -(-1) = 1$$
So, $$k^0 = -k$$ is true.
5. **Conclusion:** All three statements I, II, and III are true.
**Final answer:** (E) I, II and III
Solve Radical Equation 132Cf4
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