Solving Systems of linear equations
Oh the joys of algebra
Pros and Cons
Pros: It's a visual, and it can be a simpler method when stuck.
Cons: It's only an estimate, and it is harder to show work.
Substitution
Pros: Easy with coefficient of one.
Cons: Time consuming without a coefficient of one.
Elimination
Pro: Can be the fastest way.
Cons: Can get confusing when multiplying when negatives are involved.
The Three Methods
Graphing
Substitution
Elimination
Important Steps
- Solve both equations for y.
- Use rise and run.
- Check your answer by substituting for the variables.
Substitution
- Always check your work.
- Show work.
Elimination
- Always have a negative and a positive variable.
- Again check your work.
- If multiplying, make sure to change the whole equation.
- Show your work.
Frequently Asked Questions
The easiest method is substitution. Although many methods can be easier for other people. Elimination is typically the fastest method
Which method should I use?
Graphing can be used when both equations are solved for y and the answer can be an estimate
Substitution can be used when both equations are solved for the same variable, or have a coefficient of 1 or -1 and if either equation is solved for a variable.
Elimination can be used when one equation is positive and the other is negative.