|- 8,9|-|-3,4|

To simplify the expression \(| -8.9 | - | -3.4 |\), we start by finding the absolute values:

1. \(| -8.9 | = 8.9\)
2. \(| -3.4 | = 3.4\)

Now substituting these values back into the expression:

\[ 8.9 - 3.4 \]

Now, perform the subtraction:

\[ 8.9 - 3.4 = 5.5 \]

So, the result of the expression \(| -8.9 | - | -3.4 | = 5.5\).