First line: [tex]\;y=0.5x+8[/tex]
If you want another line perpendicular to this one, the product of the slopes must be equal to -1.
For the first line: a = 0.5
Then for the perpendicular one, it shloud be a = -2
-2×0.5 = -1
We have then two lines:
[tex]y=0.5x+8\\
y=-2x[/tex]
Sorry if my english is not quite good..
