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Linear equationsAlgebraMiddle schoolabout 1:06

Solve -8x + 9 = 3x + 4: animated lesson

A narrated, step-by-step linear equations video lesson with captions. Final answer: x = 5/11 ≈ 0.45454545.

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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 (0.4 MB) · Captions (WebVTT)

Steps on screen

1. The problem
Solving an equation
$-8~ x+9 = 3~ x+4$
2. Step by step
1. $-8~ x+9 = 3~ x+4$
  Start with the equation
2. $-11x + 9 = 4$
  Subtract 3x from both sides
3. $-11x = -5$
  Subtract 9 from both sides
4. $x = \frac{-5}{-11} = \frac{5}{11}$
  Divide both sides by -11
3. The answer
$x = \frac{5}{11} \approx 0.45454545$
x = 5/11 ≈ 0.45454545
4. Check
- x = 0.45454545: left side = 5.3636364, right side = 5.3636364 ✓

Transcript

The problem. Here is the problem: negative 8x plus 9 equals 3x plus 4. A linear equation in x: isolate x using inverse operations.

Step by step. Start with the equation. Subtract 3x from both sides. Subtract 9 from both sides. Divide both sides by negative 11.

The answer. So the answer is x equals 5 over 11 approximately 0.45454545. Doing the same operation to both sides keeps the equation balanced. Undoing addition, then multiplication, leaves x alone.

Check. x equals 0.45454545: left side equals 5.3636364, right side equals 5.3636364, which checks out.

About linear equations

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

Solve -8x + 9 = 3x + 4: Linear equations Step-by-Step Lesson