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Learn the main ways of solving linear systems in algebra II: substitution, elimination, and graphing. Step-by-step examples and methods with practice exercises included.
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Algebra II Solving Linear Systems
Main ways of solving • Substitution • Elimination • Graphing
First Method: Substitution 1) Pick an equation and isolate a variable. 2) Plug value from step 1 into the second equation. Solve. 3) Plug value of the variable from step 2 into any equation. Solve. 4) Final answers is a coordinate: (x, y)
Substitution Example 1.) x + 2y = 6 3x – 2y = 2
Substitution Examples 2.) 4x + y = 7 3.) x + 3y = 3 2x + 5y = -1 2x – 4y = 6
Second Method: Elimination 1) Change equation(s) so that you have opposite coefficients for one of the variables. 2) Add equations straight down. Solve. 3) Take value of the variable from step 2 and plug into any equation. Solve. 4) Final answer is the coordinate (x, y).
Solve the system using elimination 1.) x – y = 7 2x + y = 5
Solve the system using elimination 2.) x + 2y = -11 3x – 2y = -1
Solve the system using elimination 3.) 3x – y = 4 2x + 3y = 32
Third Method: Graphing 1) Graph both lines in the same coordinate plane. 2) Your solution is the point (x, y) where the two lines intersect. • What would be the solution if the lines are parallel? • What would be the solution if the lines overlap each other?
Homework • Systems of Linear Equations Worksheet • # 1-2, 5-8, 15-18