Mathematics · University
Solve a nonsingular 2 × 2 system · formula reference
The coefficient determinant is nonzero by construction.
Formula
The coefficient determinant is nonzero by construction.
Ax = b; eliminate one variable
Worked example
Solve 5x + y = 17 and x − 2y = 21. Enter x only. Round the final result to 4 decimal places if needed.
Multiply the first equation by 2 and add the second: (11)x = 55.
5
Prerequisites and checking
Algebra; calculus or linear algebra as appropriate to the topic. Keep units and rounding consistent. State the model conditions before applying the formula.
Further reading and review references
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