Question

Can you glance over this paper quickly to see if it looks generally right? I dont need any in depth answers just a quick glance in case something is obviously wrong

Answer 1

The equations:

`\begin{gathered} x+y=7\rightarrow y=-x+7 \\ x-y=9\rightarrow y=x-9 \end{gathered}`

Are perpendicular, because their slopes are reciprocals inverts of each other.