Systems of Linear Equations in Three Variables

 
3.1

Systems of Linear Equations in Three Variables

 
\(\blacksquare\) Two or more linear equations involving the same set of variables form a system of linear equations.
 

\(\blacksquare\) The characteristics of systems of linear equations in three variables:

  • Has three variables in each linear equation.
  • The highest power of each variable is \(1\).
 
Example of system of linear equations in three variables:
 

\(\boxed{\begin{aligned} 4x-2y+z&=2\quad \\\\ 6x+7y-z&=3 \\\\ 5x+y+2z&=7 \end{aligned} }\)

 
\(\blacksquare\) Geometrically, a linear equation in three variables forms a plane in a three-dimensional space.
 

 
\(\blacksquare\) There are three types of solutions for the systems of linear equations in three variables:
 
One Solution Infinite
solutions
No solution
The planes
intersect at only
one point
The planes
intersect in a
straight line
The planes do
not intersect at
any point
 

Methods used to solve systems of linear equations in three variables:

  • Elimination method
  • Substitution method