Solving Systems of Equations using Elimination
Here we have a system of two equations. If we write one just below the other and line up the variables, we can add the two systems together and the x's will cancel each other out, or eliminate each other.
Sometimes the equations will not automatically eliminate a variable by adding them together, so you need to subtract or multiply first. Here is a good explanation of that: http://mbaker.columbiastate.edu/AlgebraTips_pages/Solving%20Systems%20of%20Equations%20by%20Elimination.htm.
Here are some more examples of several different ways to solve by elimination: http://mathlife.net/AlgebraI/Systems
/SystemsElimination/SystemsEliminationNotes.html.
Try doing these examples and then read up on what happens when you get a "funny" answer: http://www.austincc.edu/powens/+BusEco/HTML/4-1/4-1.html#elimination.
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PRACTICE
Work out these problems and then check your answers with the answers provided: http://www.algebra-class.com/systems-of-equations-practice.html
ASSESS
Test yourself: http://teachers.henrico.k12.va.us/math/hcpsalgebra1/Documents/9-3/solvsystelimaddsub.htm
When you are done, make sure to return to the Solving Systems main page and do the activities there.
PRACTICE
Work out these problems and then check your answers with the answers provided: http://www.algebra-class.com/systems-of-equations-practice.html
ASSESS
Test yourself: http://teachers.henrico.k12.va.us/math/hcpsalgebra1/Documents/9-3/solvsystelimaddsub.htm
When you are done, make sure to return to the Solving Systems main page and do the activities there.