4-9-8.•5

To perform the operation \( 4 - 9 - 8 \cdot 5 \), we should follow the order of operations (parentheses, exponents, multiplication and division from left to right, addition and subtraction from left to right, often abbreviated as PEMDAS).

First, we calculate \( 8 \cdot 5 \):

\[ 8 \cdot 5 = 40 \]

Now, we can rewrite the expression:

\[ 4 - 9 - 40 \]

Next, we perform the subtraction from left to right:

1. Calculate \( 4 - 9 \):

\[ 4 - 9 = -5 \]

2. Now, subtract \( 40 \):

\[ -5 - 40 = -45 \]

Therefore, the final answer is:

\[ \boxed{-45} \]