T(0.2+1.7)=0.22+0.54
1.9t=0.22+0.54
1.9t=0.76
t=0.76:1.9
t=0.4
z(5.6-2-0.7)=7-2.65
2.9z=7-2.65
2.9z=4.35
z=4.35:2.9
z=1.5
750 делишь на 2=375 375*1000=375000
510/2+(15x)=285
255 + 15x = 285
15x = 285-255
15x = 30
x = 30/15
x = 2
Ответ: x = 2
2^(2x-9)<1
2^(2x-9)<2^0
2x-9<0
2x<9
x<4,5
Как то так
8 8
6 4 10
6 12 18
___________
6 6
5 9 14
5 15 20