Math 99
Study Guide for 8.4 and 8.5:
In these sections, you learned how to…
8.4 Systems of Linear Equations in 3 variables
 Understand the geometry of systems of three equations in three variables
(Different solution possibilities: single solution (1 case), infinitely many
solutions (2 cases), and no solution (3 cases))
 Solve linear systems with 3 equations, 3 variables by elimination
 Solve linear systems with 3 equations, 3 variables where some of the equations
have missing terms
 Solve special systems with 3 equations, 3 variables (that have no solution or
infinitely many solutions)
8.5 Applications of Systems of Linear Equations
 Solve geometry problems using two variables
 Solve money problems using two variables
 Solve mixture problems using two variables
 Solve distance-rate-time problems using two variables
 Solve problems with three variables using a system of three equations