Let's solve the equations one by one:

First equation:
11.3x - 5.2 = 1.3x + 7.4

Subtract 1.3x from both sides:
10x - 5.2 = 7.4

Add 5.2 to both sides:
10x = 12.6

Divide by 10:
x = 1.26

Second equation:
7.3 - (5.1 - x) = 1.8
7.3 - 5.1 + x = 1.8
2.2 + x = 1.8

Subtract 2.2 from both sides:
x = -0.4

Therefore, the solutions to the system of equations are x = 1.26 and x = -0.4.