Answer
The system has an infinite number of solutions.
Solution set = $\{(x,y)\ |\ x-2y=4\}$
Work Step by Step
Graph each line
(plot two points per line, such as the interceptcs)
$x-2y=4:\quad \left[\begin{array}{lll}
x=0 & ... & y=0\\
-2y=4 & & x-0=4\\
y=-2 & & x=4\\
(0,-2) & & (4,0)
\end{array}\right]$
$2x-4y=8:\quad \left[\begin{array}{lll}
x=0 & ... & y=0\\
-4y=8 & & 2x-0=8\\
y=-2 & & x=4\\
(0,-2) & & (4,0)
\end{array}\right]$
The lines coincide.
The system has an infinite number of solutions.
$\{(x,y)\ |\ x-2y=4\}$
