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Solving a System of Three Linear Equations Using Cramer's Rule

To solve a system of three linear equations with three variables using Cramer's rule, the procedure is similar to solving a system of two equations, but requires evaluating 3imes33 imes 3 determinants. Follow these seven steps:

  1. Evaluate the main determinant DD, using the coefficients of the variables.
  2. Evaluate the determinant DxD_x by using the system's constants in place of the xx coefficients.
  3. Evaluate the determinant DyD_y by using the system's constants in place of the yy coefficients.
  4. Evaluate the determinant DzD_z by using the system's constants in place of the zz coefficients.
  5. Find the values of xx, yy, and zz using the formulas x=DxDx = \frac{D_x}{D}, y=DyDy = \frac{D_y}{D}, and z=DzDz = \frac{D_z}{D}.
  6. Write the final solution as an ordered triple (x,y,z)(x, y, z).
  7. Check that the ordered triple is a valid solution by substituting it back into all three original equations.

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Updated 2026-05-25

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