To solve the equation \( x^{-3} = \frac{1}{x^?} \), we need to express both sides in a similar form.
Recall that \( x^{-3} \) can be rewritten as: \[ x^{-3} = \frac{1}{x^3} \]
Now we can set the two expressions equal to each other: \[ \frac{1}{x^3} = \frac{1}{x^?} \]
Since the fractions are equal, we can equate the denominators: \[ x^3 = x^? \]
From this, we can conclude that: \[ ? = 3 \]
Thus, the answer is \( ? = 3 \).