Answer
$0$ to the power of any value is 0. Yet $\frac{0}{0}$ is undefined. The denominator can't be 0. Hence, $a$ may not equal 0.
Work Step by Step
$0$ to the power of any value is 0. Yet $\frac{0}{0}$ is undefined. The denominator can't be 0. Hence, $a$ may not equal 0.