For this case we have to by definition, if two lines are perpendicular then the product of its slopes is -1.
That is to say:
![m_ {1} * m_ {2} = - 1](https://img.qammunity.org/2020/formulas/mathematics/high-school/bmbuwrtpmwf6qqw1n50skztkvkgpuhgvuw.png)
We have the following equation:
![y = -2x + 8](https://img.qammunity.org/2020/formulas/mathematics/middle-school/rm24tkq6emqxi4zqnoao3dwcvzg8ntzqo4.png)
So:
![m_ {1} = - 2](https://img.qammunity.org/2020/formulas/mathematics/college/echgtwmn427rpavi11q9txxgdnsihp39ek.png)
Thus:
![m_ {2} = \frac {-1} {m_ {1}}\\m_ {2} = \frac {-1} {- 2}\\m = \frac {1}{2}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/dg7zmxoziha3mcbhlt48me8g4wklrsdx4v.png)
Thus, a line perpendicular to the given line must have slope
![m = \frac {1} {2}.](https://img.qammunity.org/2020/formulas/mathematics/middle-school/dqrf2ejp49nayzr7ul3equ7871hnuig2ei.png)
Option A:
![x + 2y = 8\\2y = -x + 8\\y = - \frac {1} {2} x + 4](https://img.qammunity.org/2020/formulas/mathematics/middle-school/7ypjxj2s706t7ksfns5eehlwk6v1bkawvo.png)
It is not perpendicular!
Option B:
![x-2y = 6\\2y = x-6\\y = \frac {1} {2} x-3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/bx9l7gluqlqhdgmgsn6z3tictp1cf6yslj.png)
If it is perpendicular!
Option C:
![2x + y = 4\\y = -2x + 4](https://img.qammunity.org/2020/formulas/mathematics/middle-school/5ae2357sopdxjc0grpnemwnsaki6thbn7t.png)
It is not perpendicular!
Option D:
![2x-y = 1\\y = 2x-1](https://img.qammunity.org/2020/formulas/mathematics/middle-school/glgrgrqbyv5d45ii9htxxacnlgzwd3v3w9.png)
It is not perpendicular!
The correct option is option B
ANswer:
Option B