<span> 9t+4t-286=0
13t-286=0
13t=0+286
t=286:13
t=22
</span><span>25x-16x+54=162
</span>9x+54=162
9x=162-54
9x=108
x=108:9
x=12
(2,8 - х) : 0,3 = 5
2,8-х=1,5
-х=-2,8+1,5<span> <span>
х=1,3</span></span>
А * 12+8*2
1*12+8*2=28
2*12+8*2=40
4*12+8*2=64
4/5=4:5•100=0.8•100= 80 %
Ответ : 80%