Respuesta :

Answer:

(12+3x)x

Step-by-step explanation:

1-  12x+3x  15x

2-   12x+3x 15x

3-   13x+4x  17x

4-  15x

All are equivalent except for (12 + 3x)x


EXPLANATION

(12 + 3x)x ends up being an exponential value while the rest simplify out to 15x