Wetzel

Math 102

4.2 – Systems of Linear Equations:

Substitution Method

Substitution Method:  ( 1 of 3 methods to solve a linear system )

            To Solve:  ( 2 equations with 2 variables )

                        1.)  Solve for one of the variables in one of the equations.

                        2.)  Substitute this value into the other equation and solve for the remaining variable.

                        3.)  Substitute this value into one of the original equations and solve for the remaining variable.

                        4.)  Write the answer as an ordered pair.

Examples:

1.)                                                                         2.) 

3.) 

·        Infinitely Many Solutions:   All variables cancel and the remaining equation is TRUE.

·        No Solution:   All variables cancel and the remaining equation is FALSE.

Advantages vs. Disadvantages of the Substitution Method