Respuesta :

Answer:

3x+9

Step-by-step explanation:

Hope this helped!

Answer:

3x+9

Step-by-step explanation:

Remember that like terms can combine. 7x and -4x are like terms, and they combine to get 3x. 12 and -3 are like terms, and they combine to get 9. Therefore, the simplified expression is 3x+9.