Practice Objectives
  • Demonstrate the ability to solve a system of linear equations using substitution
  • Demonstrate the ability to solve a system of linear equations using elimination

Practice Solving a Two-Variable Linear System with Substitution and Elimination


Instructions:

Answer 7/10 questions correctly to pass.


Problem:

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The Substitution Method:

  1. Solve either equation for one of the variables
    • Look for a variable with a coefficient of 1 or -1
  2. Substitute in for that variable in the other equation
  3. Solve the linear equation in one variable
  4. Substitute the known value into either original equation and solve for the other unknown
  5. Check the solution

The Elimination Method:

  1. Write both equations in standard form
    • ax + by = c
  2. Transform the equations so that the coefficients of one pair of variable terms are opposites
    • Find the least common multiple (LCM) of the chosen coefficients
    • Multiply both sides of each equation by the necessary numbers to make the chosen coefficients opposites
  3. Add the two left sides of the equations together, set this equal to the sum of the two right sides of the equations
    • This will eliminate one variable
  4. Solve the linear equation in one variable
  5. Find the other unknown using substitution
  6. Check the solution

Step-by-Step:


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$$y = $$

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Wrong Answers: 0 of 3

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Wow! You have mastered Solving Linear Systems in Two Variables!

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