17a Sin²t-2Sint*Cost+Cos²t=1-2Sin2t
1-2Sin2t=1-2Sin2t
17б 2Cos²t=Sin²t+Cos²t+Cos²t-Sin²t
2Cos²t=2Cos²t
X/9 - 7/9 = 3 7/9
х/9 = 34/9 + 7/9
х/9 = 41/9
х = 41/9 * 9
х = 41
41/9 - 7/9 = 3 7/9
34/9 = 3 7/9
3 7/9 = 3 7/9
5 4/15 - x/15 = 4 7/15
79/15 - х/15 = 67/15
х/15 = 79/15 - 67/15
х/15 = 12/15
х = 12/15 * 15
х = 12
79/15 - 12/15 = 67/15
67/15 = 67/15
4 7/15 = 4 7/15
<span>3 18/19+ x/19= 15/19
</span>75/19 + х/19 = 15/19
х/19 = 15/19 - 75/19
х/19 = - 60/19
х = - 60/19 * 19
х = - 60
75/19 + (- 60/19) = 15/19
75/19 - 60/19 = 15/19
15/19 = 15/19
1.)12,8-11,36=1,44
2)5,2*2,3=11,96
3)1,44+11,96=13,4
4)13,4:0,6=22,(3)