Ответ:

Пошаговое объяснение:

2.1+(4.4-6.9)

2.1+(-2.5)

2.1-2.5

= - 0.4

-1/3-(-1/6+8/12)

-1/3-1/2=5/6=0.83

-(0.3-Х)+1.2= - 3.8

-0.3+Х+1.2= - 3.8

0.9+Х= - 3.8

Х=-3.8-0.9

Х= - 4.7

-1.3+(2.8-3.1)

-1.3+(-0.3)

-1.3-0.3= - 1.6

1/4-(3/8+11/16)

1/4-17/16

-13/16=0.81

4.1+(0.2-Х) = - 1.9

4.1+0.2-Х= - 1.9

4.3-Х= - 1.9

-Х= - 1.9-4.3

-Х= - 6.2

Х=6.2