Respuesta :

Answer:

Step-by-step explanation:

12x+9=3x+21

-3x     -3x

9x+9=21

   -9    -9

9x=12

/9   /9

x= 4/3

Answer:

[tex]\frac{4}{3}[/tex] or 1 [tex]\frac{1}{3}[/tex]

Step-by-step explanation:

12x + 9 = 3x + 21

12x - 3x = 21 - 9

9x = 12

x = [tex]\frac{4}{3}[/tex] or 1 [tex]\frac{1}{3}[/tex]