Answer
(a) $\frac{5\pi}{4}$
$-\frac{11\pi}{4}$
(b) $\frac{\pi}{4}$
$-\frac{15\pi}{4}$
Work Step by Step
(a) $-\frac{3\pi}{4}+2\pi=-\frac{3\pi}{4}+\frac{8\pi}{4}=\frac{5\pi}{4}$
$-\frac{3\pi}{4}-2\pi=-\frac{3\pi}{4}-\frac{8\pi}{4}=-\frac{11\pi}{4}$
(b) $-\frac{7\pi}{4}+2\pi=-\frac{7\pi}{4}+\frac{8\pi}{4}=\frac{\pi}{4}$
$-\frac{7\pi}{4}-2\pi=-\frac{7\pi}{4}-\frac{8\pi}{4}=-\frac{15\pi}{4}$
