Solve a problem

Linear equationsAlgebraMiddle schoolabout 0:53

Solve 8(x + 5) = 4x - 7: animated lesson

A narrated, step-by-step linear equations video lesson with captions. Final answer: x = -47/4 ≈ -11.75.

SpeedLanguage

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
$8~\left( x+5\right) = 4~ x-7$
2. Steps, part 1
1. $8~\left( x+5\right) = 4~ x-7$
  Start with the equation
2. $8x + 40 = 4x - 7$
  Simplify each side (distribute and combine like terms)
3. $4x + 40 = -7$
  Subtract 4x from both sides
4. $4x = -47$
  Subtract 40 from both sides
3. Steps, part 2
1. $x = \frac{-47}{4} = -\frac{47}{4}$
  Divide both sides by 4
4. The answer
$x = -\frac{47}{4} \approx -11.75$
x = -47/4 ≈ -11.75
5. Check
- x = -11.75: left side = -54, right side = -54 ✓

Transcript

The problem. Here is the problem: 8(x plus 5) equals 4x minus 7. A linear equation in x: isolate x using inverse operations.

Steps, part 1. Start with the equation. Simplify each side (distribute and combine like terms). Subtract 4x from both sides. Subtract 40 from both sides.

Steps, part 2. Divide both sides by 4.

The answer. So the answer is x equals negative 47 over 4 approximately negative 11.75. Doing the same operation to both sides keeps the equation balanced. Undoing addition, then multiplication, leaves x alone.

Check. x equals negative 11.75: left side equals negative 54, right side equals negative 54, which checks out.

About linear equations

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

Solve 8(x + 5) = 4x - 7: Animated Step-by-Step Lesson