a. $x=−\frac{\sqrt{2}}{3}$ b. $\sin \theta=\frac{\sqrt{7}}{3}$, $cos \theta=-\frac{\sqrt{2}}{3}$, $tan \theta=−\frac{\sqrt{14}}{2}$, $csc \theta=\frac{3\sqrt{7}}{7}$, $sec \theta=−\frac{3\sqrt{2}}{2}$, $cot\theta=-\frac{\sqrt{14}}{7}$