Algebra Tool

Elimination Method Calculator

Free elimination method calculator for solving systems of linear equations. Get step-by-step solutions with the addition/subtraction method and variable elimination. Perfect for algebra students learning to solve systems using elimination.

Last updated: December 15, 2024

Step-by-step elimination process
Automatic solution verification
Handles special cases (no solution, infinite solutions)

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Elimination Method Calculator
Solve systems of equations by elimination

Enter in the form: ax + by = c

Enter in the form: ax + by = c

Solution Found

x-value

x = 2

y-value

y = 3

Eliminated Variable:

y

Step-by-Step Solution:

Step 1: Write the system of equations
x + y = 5 ... (1)
2x - y = 1 ... (2)
Step 2: Add equations to eliminate y
(1) + (2): x + y + 2x - y = 5 + 1
3x = 6
x = 2
Step 3: Substitute x = 2 into equation (1)
2 + y = 5
y = 3

Verification:

Check: (2) + (3) = 5 ✓ and 2(2) - (3) = 1 ✓

Elimination Method Tips:

  • • Add or subtract equations to eliminate one variable
  • • Multiply equations by constants to make coefficients match
  • • Look for variables with same or opposite coefficients
  • • Always verify your solution in both original equations
  • • If 0 = 0, infinite solutions; if 0 = non-zero, no solution

Elimination Method Applications & Types

Addition Method
Add equations to eliminate a variable

Example system

x + y = 5
2x - y = 1

Add equations when coefficients are opposite

Subtraction Method
Subtract equations to eliminate a variable

Example system

2x + y = 7
2x - y = 3

Subtract equations when coefficients match

With Multiplication
Multiply equations first to match coefficients

Example system

2x + 3y = 8
3x - 2y = 1

Multiply to create matching coefficients

No Solution Systems
Parallel lines that never intersect

Result

0 = 5 (False)

Elimination leads to contradiction: no solution

Infinite Solutions
Same line represented differently

Result

0 = 0 (True)

Elimination leads to identity: infinite solutions

Three Variable Systems
Extended elimination for 3+ equations

Process

Multiple eliminations

Eliminate variables systematically, one at a time

Quick Example Result

For system: x + y = 5, 2x - y = 1

x-value

x = 2

y-value

y = 3

How the Elimination Method Works

The elimination method is a systematic algebraic approach to solving systems of equations by adding or subtracting equations to eliminate one variable. This method is particularly effective when variables have convenient coefficients that are equal or opposite, making it often faster than substitution for many systems.

The Elimination Process

Step 1: Write both equations in standard form (ax + by = c)
Step 2: Multiply equations (if needed) to match coefficients
Step 3: Add or subtract equations to eliminate one variable
Step 4: Solve the resulting single-variable equation
Step 5: Substitute back to find the other variable
Step 6: Verify the solution in both original equations

This systematic approach ensures accuracy and helps identify special cases.

When to Use Elimination Method

The elimination method is most efficient when variables have coefficients that are equal, opposite, or easily made to match through multiplication. It's particularly useful when you want to avoid fractions during the solving process, as it often keeps calculations cleaner than the substitution method.

  • Variables have the same coefficient (subtract equations)
  • Variables have opposite coefficients (add equations)
  • Coefficients are easily matched by simple multiplication
  • System has integer coefficients that work well together
  • You want to avoid the fractions common in substitution

Sources & References

  • Elementary and Intermediate Algebra - Bittinger, Ellenbogen, Johnson (6th Edition)Comprehensive coverage of elimination method techniques
  • College Algebra - Blitzer (7th Edition)Systems of equations and elimination method applications
  • Khan Academy - Systems of Equations: EliminationStep-by-step video tutorials and practice problems

Elimination Method Example

Step-by-Step Solution
Solve the system: x + y = 5 and 2x - y = 1 using elimination method

Given System:

Equation 1: x + y = 5
Equation 2: 2x - y = 1

Solution Steps:

  1. Step 1: Write the system of equations
  2. x + y = 5 ... (1)
  3. 2x - y = 1 ... (2)
  4. Step 2: Add equations to eliminate y
  5. (1) + (2): x + y + 2x - y = 5 + 1
  6. 3x = 6
  7. x = 2
  8. Step 3: Substitute x = 2 into equation (1)
  9. 2 + y = 5
  10. y = 3

Solution: x = 2, y = 3

Check: (2) + (3) = 5 ✓ and 2(2) - (3) = 1 ✓

Subtraction Example

3x + y = 10, 3x - y = 2

Subtract: 2y = 8 → y = 4, x = 2

Multiplication Example

2x + 3y = 7, 3x - y = 5

Multiply second by 3, then add

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