Final Answer:
x = -18
Solution:
equation: 12(x + 9) = -108
Step 1: divide both sides by 12.
12(x + 9) -108
______ = _____ 
 12 12
 
 -108
x + 9 = ____ (solve -108/12)
 12
Step 2: subtract 9 in both sides.
x + 9 = -9
x + 9 - 9 = -9 - 9
Last step: solve for x.
x = -9 - 9 
x = -18
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