Wetzel

Math 110

6.2(9.2) – Systems of Linear Equations in More Than Two Variables

Systems of Linear Equations with 3 Equations and 3 Variables –

            To Solve:

1.)    Choose any two equations and eliminate any one of the variables.  This forms a fourth equation with only two variables.

2.)    Choose another pair of equations and eliminate the SAME variable.  This forms a fifth equation with the same two variables as the fourth.

3.)    Put equations 4 and 5 together to form a system of linear equations with only two equations and two variables.  Solve this system.

4.)    Substitute these values into one of the original equations and solve for the third variable. 

5.)    Write your answer as an ordered triple.

Ex.:

1.)                       2.) 

3.)                           4.) 

**Note:  Homogeneous  systems all have the trivial solution, (0, 0, 0).

HW:     5^th and 6^th Ed. p.539 #5-25odd