To solve these equations, we can start by simplifying them:

1) 0.75x + 20y = 95
2) 0.5u - 0.6u = 0 => -0.1u = 0 => u = 0
3) 0.32x - 25y = 7
4) 0.4u + 1.7u = 10.9 => 2.1u = 10.9 => u = 10.9 / 2.1 = 5.19

Now, we can substitute the values of u into the equations:

1) 0.75x + 20y = 95
0.75x + 20y = 95
0.75x + 20(0) = 95
0.75x = 95
x = 95 / 0.75
x = 126.67

2) 0.32x - 25y = 7
0.32(126.67) - 25y = 7
40.54 - 25y = 7
-25y = 7 - 40.54
-25y = -33.54
y = -33.54 / -25
y = 1.34

Therefore, the solutions to the equations are:
x = 126.67
y = 1.34
u = 5.19