Linear Combination Calculator

Solve systems of linear equations using the elimination method with step-by-step solutions

System of Linear Equations

First Equation

x+y=

Format: a₁x + b₁y = c₁

Second Equation

x+y=

Format: a₂x + b₂y = c₂

Solution

Enter coefficients for both equations to solve the system

Example: 2x + 3y = 7 and x - y = 1

Example: Linear Combination Method

System of Equations

2x + 3y = 7
x - y = 1

Solution Steps

Step 1: Multiply equation 2 by -2 to eliminate x

Step 2: 2x + 3y = 7 and -2x + 2y = -2

Step 3: Add equations: 5y = 5, so y = 1

Step 4: Substitute: x - 1 = 1, so x = 2

Solution: x = 2, y = 1

Linear Combination Method

1

Elimination

Multiply equations by constants to eliminate one variable

Create opposite coefficients for one variable

2

Addition

Add the modified equations together

One variable cancels out

3

Substitution

Solve for remaining variable, then substitute back

Find both variable values

Solution Types

Unique Solution

One point where lines intersect (x, y)

No Solution

Parallel lines (0 = c, where c ≠ 0)

Infinite Solutions

Same line (0 = 0 after elimination)

LCM Method

m₁ = LCM(a₁,a₂)/a₁, m₂ = -LCM(a₁,a₂)/a₂

Understanding Linear Combination Method

What is Linear Combination?

The linear combination method (also called elimination method) solves systems of linear equations by strategically combining equations to eliminate variables. This systematic approach reduces complex systems to simpler ones that can be solved step by step.

How It Works

  • Multiply: Scale equations by appropriate constants
  • Add: Combine equations to eliminate one variable
  • Solve: Find the remaining variable
  • Substitute: Back-solve for other variables

Applications

  • Engineering systems analysis
  • Economics and optimization
  • Physics and chemistry balancing
  • Computer graphics transformations
  • Network flow problems

Advantage: The linear combination method is often more efficient than substitution for systems where coefficients have common factors or are already opposites.

Strategy Selection

When to Use Linear Combination:

  • • Coefficients are integers with common factors
  • • Variables have opposite or equal coefficients
  • • Fractions would complicate substitution
  • • Multiple variables need elimination

Multiplier Selection:

  • • Use LCM method for general cases
  • • Use ±1 when coefficients are equal/opposite
  • • Choose strategy that avoids fractions
  • • Eliminate variable with simpler coefficients