To find x, we have to put everything in base 6 and continue to simplify. Since we know that 216 is 6^3, we can replace that.
6^x = 1/216
6^x = 1/(6^3)
Now, when there is a power in the denominator, we know we can move it to the numerator by making it negative. We can do that to get the bases to match.
6^x = 1/(6^3)
6^x = 6^-3
Now that they are both put in simple base 6 systems, we can just eliminate the bases and assume that the powers are equal. This lets us know that x = -3.
