Sistema Linear 3×3 (Cramer)

x = det_x/det.
Created by
Renato Passos, Eng. de Software
Reviewed by
Renato Passos, Eng. de Software

Last updated: Apr 18, 2026

x
2,0000
y
3,0000
z
4,0000

Formula

Cramer 3×3

About this calculator

The 3×3 Linear System Calculator solves systems of three equations with three unknowns (x, y, z) using Cramer's Rule. The method calculates the determinant of the main matrix (det) and the determinants of the modified matrices (det_x, det_y, det_z), where each column is replaced by the constants. The solutions are given by x = det_x/det, y = det_y/det, z = det_z/det, provided det ≠ 0.

This tool is useful for students of linear algebra, engineering, and exact sciences who need to solve linear systems quickly. For example, in problems involving electrical circuits, chemical equilibrium, or analytic geometry, 3×3 systems frequently appear. The calculator automates the calculations, avoiding manual errors and saving time.

Important precautions: Cramer's Rule only works if the main determinant is non-zero (consistent and independent system). If det = 0, the system may be inconsistent or have infinite solutions. Additionally, for large systems, other methods (like Gaussian elimination) are more efficient. Ensure coefficients are entered correctly, including negative signs.

The calculator accepts integer or decimal numbers. Results are displayed with up to 4 decimal places. For systems with zero determinant, an error message will be shown. Use a period as decimal separator and avoid fractions, converting them to decimals before entering.

Frequently asked questions

What if the main determinant is zero?

If det = 0, the system cannot be solved by Cramer's Rule. This indicates the system is either inconsistent or has infinite solutions. Try Gaussian elimination or check if the equations are dependent.

Can I input fractions in the calculator?

No, the calculator accepts only decimal or integer numbers. Convert fractions to decimals before entering, for example, 1/2 should be entered as 0.5.

How do I enter negative coefficients?

Use the minus sign (-) before the number. For example, for -3, type -3. Make sure all fields are filled correctly.

Does the calculator show the calculation steps?

No, it only displays the final result (x, y, z) or an error message. To see intermediate determinants, use other tools or calculate manually.

What is the precision of the results?

Results are rounded to up to 4 decimal places. If you need more precision, use a scientific calculator or specialized software.

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