Section 4.2
Solving Systems of Linear
Equations in 3 Variables.
Small differences…
 This time, the solution is an ordered triple:
(x, y, z).
 EX: Is (2, -2, 1) a solution to:
3x + 2y + z = 3
2x – 3y – 2z = 8
-2x+ 4y + 3z = -9
To Solve (Elimination Method)
 Select 2 equations and multiply to get one
variable to have opposite coefficients. Add
to eliminate that variable.
 Select 2 DIFFERENT equations and eliminate
the same variable.
 Solve for the 2 remaining variables using
methods from section 4.1.
 Substitute the values just found into any of
the original equations and solve for the 3rd
variable.