To solve the equation \(-3x - 9 = -21\), we will go through it step-by-step and fill in the missing parts.
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Start with the equation: \[ -3x - 9 = -21 \]
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Add 9 to both sides: \[ -3x - 9 + 9 = -21 + 9 \] This simplifies to: \[ -3x = -12 \]
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Divide both sides by -3: \[ x = \frac{-12}{-3} \] This simplifies to: \[ x = 4 \]
So the completed solution looks like this:
- Start with: \(-3x - 9 = -21\)
- Add 9 to both sides: \(-3x = -12\)
- Divide both sides by -3: \(x = 4\)