What is the number of solutions to $|x - 2| = |x - 4|$?
4
- Step 1: Understanding the equation - The equation $|x - 2| = |x - 4|$ says the distance from $x$ to 2 is the same as the distance from $x$ to 4.
- Step 2: Using the property of absolute values - The point that is equidistant from two numbers lies exactly at their midpoint.
- Step 3: Finding the midpoint - Midpoint of 2 and 4 is: \[ \frac{2 + 4}{2} = 3 \]
- Step 4: Conclusion from symmetry - The only value of $x$ satisfying the equation is $x = 3$.
- Step 5: Verification - $|3 - 2| = 1$ and $|3 - 4| = 1$, so both sides are equal.
- Step 6: Final answer - There is exactly 1 solution, matching option (1).
For any natural number $k$, let $a_k = 3^k$. The smallest natural number $m$ for which \[ (a_1)^1 \times (a_2)^2 \times \dots \times (a_{20})^{20} \;<\; a_{21} \times a_{22} \times \dots \times a_{20+m} \] is: