Z1/z2 = (14 - 6i)/(11-7i) = (14 - 6i)(11 + 7i)/(121 + 49) = (154 - 66i + 98i + 42)/170 = (196 + 32i)/170 = (98 + 16i)/85
arg(z1/z2) = arctg(16/98) = arctg(8/49)
z2/z1 = (11-7i)/(14-6i) = (11-7i)(14+6i)/(196+36) = (154-98i+66i+42)/232 = (196-32i)/232 = (39 - 8i)/58