Answer
$x^{40}$
Work Step by Step
When dividing exponential expressions with the same non-zero base, subtract the exponent of the denominator from the exponent of the numerator:
$$\frac{x^{30}}{x^{(-10)}}$$
$$=x^{(30-(-10))}$$
$$=x^{(30+10)}$$
$$=x^{40}$$
