3/4*1,8*1 1/5:0,07/1/5:0,49*2 5/8=21.6
3/4*18/10=27/20
27/20*1 1/5=27/20*6/5=81/50
81/50:0.07=81/50:7/100=81/50*100/7=162/7
1/5:0.49=1/5:49/100=1/5*100/49=20/49
20/49*2 5/8=20/49*21/8=15/14
162/7:15/14=162/7*14/15=108/5=21.6
-9х+7х= -14+26
-2х=12
х= -6
30*3/5= 18 (девочек) Ответ: 18 девочек
<span>Б) 4,72c+2,8c=78,96
7,52с=78,96
с=10,5
</span>
3cos в квадрате x или 3cos2x?