Answer:
x= -12
Explanation:
3(x+7)+6= -9
3x+21+6= -9
subtract 6 from both sides that gives you your equation that you can work with.
3x+21= -15
then subtract 21 from both sides that gives you
3x/3 = -36/3
the 3 cancels out and leaves you with -36 divided by 3
your answer is -12