Showing students how to solve systems of linear
equations using the alternative version of Gaussian
elimination allows them to avoid becoming inundated
with fraction computations. For Example 2, if the
operation between any two integers counts as one
computation, then using the traditional method to solve
the system of equations results in 58 computations; the
alternative method results in 46 computations. Because
the alternative method produced 21% fewer
computations than the traditional method, students are
less likely to get lost in the intermediate computations and are more able to focus on the overall purpose of
the method.
Note again that the alternative method can be used
for systems of rational equations and can be followed
fairly mechanically for rational systems containing
n
equations with n variables. In the event that the system
of equations has infinitely many solutions or no
solution, the idea behind the alternative method is the
same: get 0’s for entries above and below the leading
non-zero entry in each row, then divide each row by
the value of this non-zero entry. The following
example illustrates this point (Example 3 in Figure 6).