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4. Which of the following lines is perpendicular to y = -2X + 8?

A. X + 2y = 8
B. X-2y = 6
C. 2x + y = 4
D. 2x - y = 1

User Geo Jacob
by
5.3k points

1 Answer

3 votes

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

We have the following equation:


y = -2x + 8

So:


m_ {1} = - 2

Thus:


m_ {2} = \frac {-1} {m_ {1}}\\m_ {2} = \frac {-1} {- 2}\\m = \frac {1}{2}

Thus, a line perpendicular to the given line must have slope
m = \frac {1} {2}.

Option A:


x + 2y = 8\\2y = -x + 8\\y = - \frac {1} {2} x + 4

It is not perpendicular!

Option B:


x-2y = 6\\2y = x-6\\y = \frac {1} {2} x-3

If it is perpendicular!

Option C:


2x + y = 4\\y = -2x + 4

It is not perpendicular!

Option D:


2x-y = 1\\y = 2x-1

It is not perpendicular!

The correct option is option B

ANswer:

Option B

User Eniss
by
5.1k points
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