Linear System 3 Variables Calculator

Enter coefficients for three equations easily. Review determinant tests, rank status, and residual accuracy checks. Save clear solution reports for study and class work.

Calculator

Formula Used

The calculator writes the system as A × X = B.

A = [[a1, b1, c1], [a2, b2, c2], [a3, b3, c3]]
X = [x, y, z]
B = [d1, d2, d3]

For a unique solution, det(A) must not be zero.

x = det(Ax) / det(A)
y = det(Ay) / det(A)
z = det(Az) / det(A)

Ax, Ay, and Az are made by replacing one column of A with B. If det(A) equals zero, the calculator compares rank(A) and rank([A|B]).

How to Use This Calculator

  1. Enter each coefficient for x, y, and z.
  2. Enter the constant on the right side of each equation.
  3. Use zero when a variable is missing.
  4. Select a solving method and decimal precision.
  5. Press Calculate to view the result above the form.
  6. Use CSV or PDF buttons to save the current result.

Example Data Table

Equation x coefficient y coefficient z coefficient Constant Expected solution
1 2 1 -1 8 x = 2, y = 3, z = -1
2 -3 -1 2 -11
3 -2 1 2 -3

About Linear Systems With Three Variables

A linear system with three variables has three equations. Each equation uses x, y, and z. The calculator reads every coefficient and constant. Then it decides whether the system has one solution, no solution, or infinitely many solutions.

Why The Result Matters

Many classroom problems only ask for x, y, and z. Real work needs more checks. A unique answer is useful only when the equations are consistent. A small determinant can make results unstable. That is why this tool also reports the determinant, matrix ranks, and residual errors.

How The Solver Thinks

The coefficients form a 3 by 3 matrix. The right side forms a constant vector. When the determinant is not zero, the system has one solution. The calculator can use Cramer’s Rule. It replaces one coefficient column at a time with the constant vector. These new determinants give x, y, and z.

If the main determinant is zero, Cramer’s Rule cannot divide safely. The calculator then compares ranks. The coefficient rank shows the independent equation count. The augmented rank includes the constants. Equal ranks with a low rank mean many solutions. Different ranks mean the equations conflict.

Good Input Practice

Enter coefficients exactly as they appear. Use zero for a missing variable. For example, write 0 for z when the equation has only x and y. Keep signs with the numbers. A negative term should be typed as a negative coefficient.

The tolerance setting controls near zero decisions. Use a small tolerance for clean integer problems. Use a larger tolerance for measured data. Precision controls displayed decimals, not the core calculation.

When To Use It

Use this calculator for algebra, matrices, physics, finance, and engineering models. It works well for simultaneous balance equations. It also helps verify manual work. The residual row is important. A residual near zero means the computed values satisfy the original equations. Large residuals show input errors, rounding issues, or an unstable system.

Exported files help track homework attempts, audit calculation choices, and share answers. CSV suits spreadsheets. PDF suits printing, grading notes, and saved records for later careful review and comparison.

Always review the status line first. Then read x, y, and z. Finally check determinant and rank details before exporting results.

FAQs

What is a three variable linear system?

It is a set of three linear equations using x, y, and z. A valid system can have one ordered triple, no ordered triple, or infinitely many ordered triples.

What does the determinant show?

The determinant shows whether the coefficient matrix is invertible. If it is not zero, the system has one unique solution.

What happens when the determinant is zero?

The calculator checks matrix ranks. Equal ranks can mean infinitely many solutions. A larger augmented rank means no solution.

Can I enter decimals?

Yes. Decimal coefficients and constants are accepted. Use the precision field to control how many decimal places appear in the result.

Why should I check residuals?

Residuals show how closely the answer satisfies each original equation. Values near zero indicate a strong match.

What is zero tolerance?

Zero tolerance decides when a very small value should be treated as zero. It helps with rounded or measured inputs.

Can this solve dependent equations?

It can identify dependent equations. When ranks match and the determinant is zero, the result reports infinitely many solutions.

What do the export buttons save?

The CSV button saves spreadsheet-friendly rows. The PDF button saves a simple report with status, determinants, ranks, solution values, and residuals.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.