Question

Are the lines y=-x-4 and 5x+5y=20 perpendicular? Explain.

a)Yes; the product of their slopes is -1.
b)No; their slopes are equal.
c)Yes; their slopes are equal.
d)No; their slopes are not equal

Answer 1

Well, which do you think the answer is?

Answer 2

The slope of a line times the slope of the perpendicular is always equal to -1, and if the slope of two lines multiplied = -1, then they are perpendicular.

Answer 3

d

Answer 4

Uh uh. What is the slope of each line?

Answer 5

b because i know their not perpendicular

Answer 6

Yep, that's correct! :)

Answer 7

so their slopes are equal??

Answer 8

Yes, both the slopes are equal to -1. -5/5 = -1.