To simplify the expression X^-1 * X^-1 * X^-1, we can use the rule of exponents that states when multiplying two numbers with the same base, we add their exponents.
Since X^-1 means the reciprocal of X, we can rewrite the expression as (1/X) * (1/X) * (1/X).
Multiplying the numerators and denominators, we get (1 * 1 * 1) / (X * X * X) = 1 / X^3.
Therefore, X^-1 * X^-1 * X^-1 simplifies to 1 / X^3.