1)2.66/3.8=0.7
2)0.81*0.12=0,0972
3)0.7-0.0972=0.6028
4)0.6028+0.0372=0.64
2x-5=2 или 2x-5=-2
2x=7 2x=3
x=3.5 x=1.5
Ответ 3.5; 1.5
Д) 3 + 11x = 203 +x
11x - x = 203 - 3
10x = 200
x = 200/10
x = 20
Б) 4a - 312 = 0
4a = 312
a = 312/4
a = 78
Г) 25-3y = 9-5y
-3y+5y = 9 - 25
2y= - 16
y = -8