Answer
(a) $(8,-12)$
(b) $(-8,12)$
Work Step by Step
(a) Reflect across the x-axis means $y\to -y$, we can obtain the corresponding point of $(8,12)$ as $(8,-12)$
(b) Reflect across the y-axis means $x\to -x$, we can obtain the corresponding point of $(8,12)$ as $(-8,12)$
