Respuesta :

Answer:

[tex]3x + 6 = 21 \\ 3x = 21 - 6 \\ 3x = 15 \\ x = \frac{15}{3} \\ x = 5[/tex]

Answer: x=5

Step-by-step explanation:

step 1:

put all the coefficients on one side and all the variables on the other, 3x=21-6

step 2:  solve the sides, 3x=15

step 3: divide, 3x/3= 15/3

step 4: simplify: x=5