Answer
$=\frac{1}{x^{24}}$
Work Step by Step
When an exponential expression is raised to a power, multiply the exponents: $$(x^{(-6)})^{4}$$
$$=x^{(-6\times4)}$$
$$=x^{(-24)}$$
A expression with a negative exponent can be simplified by moving the base from the numerator to the denominator (or vise versa):
$$=\frac{1}{x^{24}}$$