Final answer:
The first step to solving the given expression is to combine like terms.
Step-by-step explanation:
The first step to solving the given long expression is to combine like terms.
In the given expression, like terms are 3x and -3x. Adding them results in 0, so these terms cancel out.
After combining like terms, the expression becomes: 15 + 8x = 12x + 2 - 13.
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