determine which two equations represent perpendiculiar lines y=4x-8, y=1/4x+8, y=-1/4x+8, y=1/4x-8?

Question

I think b and c

No b and d not c

Answer 1

Hi,

Perpendicular lines have slopes that are negative reciprocals of each other. Except for horizontal and vertical lines, their 2 slopes multiply together and equal -1.

The first equation has a slope of 4.
The second equation has a slope of 1/4.
The third equation has a slope of -1/4.
The fourth equation has a slope of 1/4.

When slopes are the same but y intercepts are different, the lines are parallel to each other. This means equations 2 and 4 are parallel to each other.

When slopes are negative reciprocals and multiply together to equal -1, the lines are perpendicular. Since the first equation's slope is 4 and the third equation's slope -s -1/4, these multiply together to give -1: 4*-¼ = -1. So these lines are perpendicular.

Those are lines a and c.

I hope that helps!! :-)

Answer 2

line with slope m1 is perpendicular to line with perpendicular m2 if :-
(m1) (m2) = - 1

Line a)
y = 4x - 8 has m = 4

Line b)
y = (-1/4) x + 8 has m = (-1/4)

4 x (-1/4) = - 1

Lines a) and c) is answer.

Answer 3

it's b and d because the slope is the same but the have opposite y-intercepts!