-7x - 12 = (fill in the blank)x + 12

1 answer

To solve for the value that fills in the blank in the equation \(-7x - 12 = (fill in the blank)x + 12\), we can rearrange the equation:

  1. Rewrite it as: \[ -7x - 12 = bx + 12 \]

    where \(b\) is the value that we need to find.

  2. Add \(12\) to both sides: \[ -7x - 12 + 12 = bx + 12 + 12 \] Simplifying it gives: \[ -7x = bx + 24 \]

  3. Now, let's isolate \(x\): \[ -7x - bx = 24 \] Factoring out \(x\), \[ (-7 - b)x = 24 \]

  4. For this equation to hold true for all \(x\), the coefficient of \(x\) on the left (i.e., \(-7 - b\)) must equal \(0\). Therefore, we can set up the equation: \[ -7 - b = 0 \]

  5. Solving for \(b\): \[ b = -7 \]

Thus, the filled-in blank would be \(-7\). Therefore, the equation can be completed as: \[ -7x - 12 = -7x + 12 \]