Respuesta :

Sjohann417
5x + 4x = 9x 
Hope this helps!!!!
Answer: 9x 

Explanation: Both 5x and 4x have the same variable (x)  so they can add to each other. If the problem was 5x + 4y, you wouldn't be able to simplify it any more because the variables (x and y) are different.
Q&A Education