Consider the given expression,
[tex]x+y<-8[/tex]This is a strict inequality, whose boundary is formed by a straight line.
At least two points are needed to plot the line on the Cartesian Plane.
Put x=0 in the eqiation,
[tex]\begin{gathered} 0+y=-8 \\ y=-8 \end{gathered}[/tex]So the line passes through (0,-8).
Put y=0 in the equation,
[tex]\begin{gathered} x+0=-8 \\ x=-8 \end{gathered}[/tex]So the line passes through (-8,0).
Check if (0,0) is a solution of the inequality,
[tex]\begin{gathered} 0+0<-8 \\ 0<-8 \end{gathered}[/tex]This is a false statement as 0 cannot be less than -8, so (0,0) is not in the solution region.
The graph of the inequality is obtained as follows,