Decades: 1120s 1130s 1140s 1150s 1160s - 1170s - 1180s 1190s 1200s 1210s 1220s
Years: 1173 1174 1175 1176 1177 - 1178 - 1179 1180 1181 1182 1183
Births
Deaths
... + \left( \frac{b}{a} \right) x + \frac{c}{a}=0 </math> which is equivalent to <math>x^2+\frac{b}{a}x=-\frac{c}{a}.</math> Th ...