Solve for x:
3 + 9 (x + 1) = -9 - 4 (x - 1)
9 (x + 1) = 9 x + 9:
9 x + 9 + 3 = -9 - 4 (x - 1)
Add like terms. 3 + 9 = 12:
9 x + 12 = -9 - 4 (x - 1)
-4 (x - 1) = 4 - 4 x:
9 x + 12 = 4 - 4 x - 9
Add like terms. 4 - 9 = -5:
9 x + 12 = -5 - 4 x
Add 4 x to both sides:
9 x + 4 x + 12 = (4 x - 4 x) - 5
4 x - 4 x = 0:
9 x + 4 x + 12 = -5
9 x + 4 x = 13 x:
13 x + 12 = -5
Subtract 12 from both sides:
13 x + (12 - 12) = -5 - 12
12 - 12 = 0:
13 x = -5 - 12
-5 - 12 = -17:
13 x = -17
Divide both sides of 13 x = -17 by 13:
(13 x)/13 = (-17)/13
13/13 = 1:
Answer: |x = (-17)/13
