[tex]\displaystyle\bf\\+\left \{ {{tgx+tgy=2} \atop {tgx-tgy=0}} \right. \\----------\\2tgx=2\\\\tgx=1\\\\\\x=\frac{\pi }{4} +\pi n,n\in Z\\\\\\-\left \{ {{tgx+tgy=2} \atop {tgx-tgy=0}} \right. \\----------\\2tgy=2\\\\tgy=1\\\\y=\frac{\pi }{4} +\pi n,n\in Z\\\\\\Otvet \ B\ : \ \Big(\frac{\pi }{4} \ ; \ \frac{\pi }{4} \Big)[/tex]