А) 37²+37×3=1369+37×3=1480
б)25² - 25 × 15=625-25×15 =250
Sin A = BC /AB , BC = /| AB2 - AC2 = /| 81 - 32 + /| 49 = 7
Sin A = 7 / 9
1. 60:12*13=65
65+60=125
375:125=3часа
2.1/7 2/7 3/7 4/7 5/7 6/7
3.7/7 8/7 9/7 10/7 таких дробей бесконечно
4.1)5/7>2/7
2)4/15<7/15
3)2/9=26/117 2/13=18/117
26/117>18/117
4)7/25=42/150
7/30=35/150
42/150>35/150