3x+12-6x<-9

how do I do this?

First simplify 3x + 12 - 6x to - 3x - 12

Next subtract 12 from both sides

Next subtract - 9 - 12 and that would be - 21

Next divide both sides by - 3

Next lets simplify the fraction - 21/-3 into 21/3 since those two negatives make a positive.

Lastly simplify the fraction 21/3 to get the answer.

Answer: x ≥ 7