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Linear equationsAlgebraMiddle schoolabout 0:43

Solve for x: -2x - 18 = 7: animated lesson

A narrated, step-by-step linear equations video lesson with captions. Final answer: x = -25/2 ≈ -12.5.

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Video with a synthetic English voice and captions. Pick another language for subtitles in that language, or open the interactive version.

Video narrated by a synthetic voice (Piper TTS, en_US-ljspeech-high voice (LJ Speech dataset, public domain)); the steps come from our maths engine and the answer was checked independently. Download MP4 (0.3 MB) · Captions (WebVTT)

Steps on screen

1. The problem
Solving an equation
$-2~ x-18 = 7$
2. Step by step
1. $-2~ x-18 = 7$
  Start with the equation
2. $-2x = 25$
  Add 18 to both sides
3. $x = \frac{25}{-2} = -\frac{25}{2}$
  Divide both sides by -2
3. The answer
$x = -\frac{25}{2} \approx -12.5$
x = -25/2 ≈ -12.5
4. Check
- x = -12.5: left side = 7, right side = 7 ✓

Transcript

The problem. Here is the problem: negative 2x minus 18 equals 7. A linear equation in x: isolate x using inverse operations.

Step by step. Start with the equation. Add 18 to both sides. Divide both sides by negative 2.

The answer. So the answer is x equals negative 25 over 2 approximately negative 12.5. Doing the same operation to both sides keeps the equation balanced. Undoing addition, then multiplication, leaves x alone.

Check. x equals negative 12.5: left side equals 7, right side equals 7, which checks out.

About linear equations

Solve one-variable linear equations, including ones with brackets and fractions, and check the solution.

Solve for x: -2x - 18 = 7: Animated Step-by-Step Lesson