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Linear equationsAlgebraMiddle schoolabout 0:43

Solve for x: -4x + 1 = 15: animated lesson

A narrated, step-by-step linear equations video lesson with captions. Final answer: x = -7/2 ≈ -3.5.

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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
$-4~ x+1 = 15$
2. Step by step
1. $-4~ x+1 = 15$
  Start with the equation
2. $-4x = 14$
  Subtract 1 from both sides
3. $x = \frac{14}{-4} = -\frac{7}{2}$
  Divide both sides by -4
3. The answer
$x = -\frac{7}{2} \approx -3.5$
x = -7/2 ≈ -3.5
4. Check
- x = -3.5: left side = 15, right side = 15 ✓

Transcript

The problem. Here is the problem: negative 4x plus 1 equals 15. A linear equation in x: isolate x using inverse operations.

Step by step. Start with the equation. Subtract 1 from both sides. Divide both sides by negative 4.

The answer. So the answer is x equals negative 7 over 2 approximately negative 3.5. Doing the same operation to both sides keeps the equation balanced. Undoing addition, then multiplication, leaves x alone.

Check. x equals negative 3.5: left side equals 15, right side equals 15, which checks out.

About linear equations

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

Solve for x: -4x + 1 = 15: Animated Step-by-Step Lesson