Solve the system of linear equations by graphing. 4x - 4y = 20y = - 5

Question

Solve the system of linear equations by graphing.
`4x - 4y = 20`
`y = - 5`

Answer 1

First, write both equations in slope-intercept form:

`\begin{gathered} 4x-4y=20 \\ \Rightarrow-4y=20-4x \\ \Rightarrow y=(20-4x)/(-4) \\ \Rightarrow y=-5+x \end{gathered}`

The other one is already in slope-intercept form:

`y=-5`

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:

`\begin{gathered} x=0 \\ y=-5 \end{gathered}`