Respuesta :

Answer:

[tex]\boxed{ - 4x +9 x = ( - 4 + 9)x = 5x}\\[/tex]

5x is the right answer.

Answer = 5x

Explanation: Collect the like terms by calculating the sum or difference of their coefficients which would get you (-4 + 9)x
Then you calculate the sum which gets you 5x