Simplify the Expression: 5+8-9+5x-4x Step by Step

To solve this problem, we will simplify the expression $5+8-9+5x-4x$ by separately combining the constants and the variable terms.

Step 1: Simplify the constant terms.
$5 + 8 - 9 = 4$

Step 2: Simplify the variable terms.
$5x - 4x = x$

Step 3: Combine the results from steps 1 and 2.
Thus, the simplified expression is $4 + x$.

Therefore, the solution to the problem is $4 + x$, which corresponds to choice .