Answers:
- The simplified expression is -4x
- The value is -516
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Explanation:
To simplify this, we combine the coefficients. This works because all of the terms have 'x' in them and nothing else (they are all like terms). We can think of this problem as trying to evaluate -12+14-6. This simplifies to -4
So -12x+14x-6x simplifies to -4x
Afterward, we replace x with 129 to get
-4x = -4*129 = -516