2-D Systems of Equations & Substitution and Elimination

1. 1.   Solving 2-D linear systems of equations using substitution (8:12)  The video starts with a discussion on the possible numbers of solutions.  Three examples are given:
      • [Example 1] $\begin{cases}2x+4y =4\\y=x-2\end{cases}$
      • [Example 2] $\begin{cases} x+3y=6\\2x+6y = -12\end{cases}$
      • [Example 3] $\begin{cases}2x-3y=6\\4x-6y=12\end{cases}$

2.    Solving 2-D linear systems of equations using elimination by addition (9:59) The video starts with a discussion on the possible numbers of solutions.  Three examples are given:

• • • [Example 1] $\begin{cases}2x+3y =4\\-2x+7y=16\end{cases}$
    • [Example 2] $\begin{cases}x-3y=6\\4x-3y = 10\end{cases}$
    • [Example 3] $\begin{cases}2x=-6y+8\\3x-5y=2\end{cases}$