Solve the system -x + 6y = -44 and -2x + 7y = -58: animated lesson
A narrated, step-by-step systems of equations video lesson with captions. Final answer: x = 8, y = -6.
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 (0.5 MB) · Captions (WebVTT)
Steps on screen
- 1. The problemSolving an equation
- 2. Steps, part 1
- Write every equation in standard form
- Build the augmented matrix [A | b]
- Gauss–Jordan elimination
- Divide R1 by -1
- 3. Steps, part 2
- Clear column 1 using the pivot in R1
- Divide R2 by -5
- Clear column 2 using the pivot in R2
- Reduced row-echelon form
- 4. Steps, part 3
- Read off the unique solution
- 5. The answer
-x + 6y = -44; -2x + 7y = -58 ⇒ x = 8, y = -6
- 6. Check
- Equation 1: -x + 6y = -44 ✓
- Equation 2: -2x + 7y = -58 ✓
Transcript
The problem. Here is the problem: negative x plus 6y equals negative 44; negative 2x plus 7y equals negative 58. 2 linear equations in 2 unknowns (x, y).
Steps, part 1. Write every equation in standard form. Move all variable terms to the left and constants to the right. Build the augmented matrix [A | b]. Columns: x, y | constant. Gauss–Jordan elimination. Use row operations to make each pivot 1 and clear the rest of its column. Divide R1 by negative 1.
Steps, part 2. Clear column 1 using the pivot in R1. Divide R2 by negative 5. Clear column 2 using the pivot in R2. Reduced row-echelon form.
Steps, part 3. Read off the unique solution.
The answer. So the answer is x equals 8, y equals negative 6. The system has exactly one solution; substituting it back satisfies every equation.
Check. Equation 1: negative x plus 6y equals negative 44, which checks out. Equation 2: negative 2x plus 7y equals negative 58, which checks out.
About systems of equations
Solve systems of two or three linear equations by elimination and substitution.
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