Question

Please help! The line passes through (2,-4) and is perpendicular with the slope of -2

Answer 1

Given the slope is

-2 or -2/1

do you know how to find the perpendicular slope?

Answer 2

I don't know how to find the perpendicular slope - Is it the point slope formula? and thank you! =)

Answer 3

turn -2/1 upside down and get rid of the negative sign to give us

1/2

Answer 4

is that a negative reciprocal and why does it have to be a negative reciprocal?

Answer 5

yes it is a negative reciprocal and it needs to be a negative reciprocal because it is perpendicular

Answer 6

OHHHH - the answer key says the answer is y=1/2 x - 5 -- How did they get that answer - especially the -5 part?? Thank you so much!

Answer 7

Are you okay with the 1/2 part??

Answer 8

yes - got that part. I just don't understand the y intercept part (-5). :)

Answer 9

We can use

y = mx + b

were

y = -4
x = 2
m = 1/2

Substitute

-4 = (1/2)(2) + b

then multiply

-4 = 1 + b

subtract 1 from both sides

-5 = b

Answer 10

i got it.....you have to use the point slope formula with the negative reciprocal slope!! right? :)

Answer 11

You can, but I did not ...

Answer 12

o,ok...well you're a smarty :) thank you so much for your help!