First, write both equations in slope-intercept form:
[tex]\begin{gathered} 4x-4y=20 \\ \Rightarrow-4y=20-4x \\ \Rightarrow y=\frac{20-4x}{-4} \\ \Rightarrow y=-5+x \end{gathered}[/tex]The other one is already in slope-intercept form:
[tex]y=-5[/tex]Plot both equations in a coordinate plane. The intersection of those equations gives the solution (x,y):
Therefore, the solution of the system of linear equations is:
[tex]\begin{gathered} x=0 \\ y=-5 \end{gathered}[/tex]
