Question

how would you find the slope of
x=5

Answer 1

you cant

Answer 2

try picking 2 points on the line and finding the slope between them

Answer 3

This is what it says im so confused:
identify the slope and graph the equation for x=5 and y=-3

Answer 4

2 different questions? or parts?

Answer 5

Well it has a.)
then b.)
So I'm guessing questions..

Answer 6

k, lets do the y=-3 first; can you name 2 points on the y=-3 line?

Answer 7

There isn't a graph.....
but I'm guessing -1, -2?

Answer 8

that tells me that you are not aware of what the concepts are for these "equations", and its most likely becasue you are used to seeing a particular form

Answer 9

the line y=-3 has all points such that the y component is -3

(x,-3) for any value of x; soo; (-1,-3) and (5,-3) are 2 points in the y=-3 line

Answer 10

So you can pick any x.

Answer 11

correct, y=-3 only cares about the y part, x can be anything it wants to be

if we apply that to the line x=5, what do you believe that would tell us?

Answer 12

The slope?

Answer 13

no, how wold we pick to points on the line x=5? what is important about any point of the line x=5

Answer 14

if we can pick 2 points, we can define a slope

Answer 15

The y-intercept ?

Answer 16

the line y=-3 only cares about the y value; all points (x,-3) are on the line

for the other line x=5, we only care about the x values; all points (5,y) are on the line

Answer 17

The slope of any vertical line is undefined. Horizontal lines all have a slope of 0. Because x=5 is a purely vertical line, the slope is simply undefined. Do not confuse undefined with 0 as they are different.

Answer 18

So each line only cares for a certain value and x is always 0?

Answer 19

"So each line only cares for a certain value" yes, ignore the rest of your comment

Answer 20

iangu is giving you a definition that can be memorized, I am trying to prove the definitions

Answer 21

So x isn't always 0? But what about the rule y=mx+b?

Answer 22

Y=-3 is a horizontal line ( you can use (0,-3) as a reference point) and the slope is 0 because it is horizontal. Chances are the idea behind that lesson is to have you memorize these things. Proofs are only important in college and only for certain professors but tend to be complicated and unnecessary if not asked for. I am stating this out of current experience in calculus at UCF

Answer 23

thats is the form of a line that you are used to seeing; and it can be modified for the y=-3 form; but it cannot be modified for the x=5 form

Answer 24

That kind of makes sense... So then slope would always be 0?...

Answer 25

y=mx+b is merely the slope-intercept method of writing an equation and will NORMALLY tell you what the slope is, the problem is that like I said, vertical lines and horizontal lines are exceptions to the rule.

Answer 26

for y=-3, or any constant value; yes the slope is 0

Answer 27

for x=5, you can say that the slope is NOT EVEN zero

Answer 28

So that method doesn't always work... So my overall is what is the best way to REMEMBER how to find slope and y-intercept that will always work?

Answer 29

"any constant value" can be misleading. Any constant Y-value is a horizontal line with slope 0 while any constant X-value is a vertical line with an undefined slope

Answer 30

2 points on the x=5 line can be: (5,0) and (5,2)

the slope between the points is:\[\frac{2-0}{5-5}=\frac20\]since division by 0 is not allowed, this is simply undefined

Answer 31

And that is a great proof for vertical slope

Answer 32

That makes a little sense. Thank you.