1)-28.7-16.28+х=-14.2 2)34.9-х+17.4-13.4=2.8 3)19.8-х+19.1-13.2=14.8 )

Х1 =-14. 2+28.7+16.28=30.75
Х2 = 34.9+17.4-13.4-2.8=36.1
Х3 = 19.8+19.1-13.2-14.8=10.9

1)-28,7-16,28+х=-14,2
-44,98+х=-14,2
-44,98+14,2=х
-30,78=х
х=-30,78
2)34.9-х+17.4-13.4=2.8
34.9+17.4-13.4-2.8=х
36.1=х
х=36.1
3)19.8-х+19.1-13.2=14.8
19.7+19.1-13.2-14.8=х
10.8=х
х=10.8