Download Algebra II Substitution and Elimination Notes 3 Variables GOAL

Algebra II
Substitution and Elimination Notes
3 Variables
GOAL- Solve a linear system with 3 variables algebraically
SUBSTITUTION METHOD:
STEP 1: Solve one of the equations for one of its variables, (i.e
solve for x , y, or z). Then put a circle or box around everything
after the equal sign.
STEP 2: Substitute the expression from step 1 into the other
two (2) equations and simplify. (This will give you two equations
with just 2 variables).
STEP 3: Solve the new system of 2 equations and 2 variables
using either Substitution or Elimination.
STEP 4: To find the 3rd variable, Plug in the solutions for the 2
variables solved in Step 3 back into the isolated equation from
Step 1 and solve for the 3rd variable.
Strategy Suggestion. Number each of your equations at the very
start of the problem.
ALWAYS CHECK the final solution (x, y, z) by plugging it back
into each original equation.
Example: Solve the following system of equations using
Substitution/Elimination to find the solution (x, y, z)
2.
Q
IK
j)
5jc + 4y + 22 = 5
2',
3X 4 - - (
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