Question

How do you find an equation of the line that passes through the points (2,1) and (2,5)?

Answer 1

I know the formulas; however I just can't seem to get the right answer...

Answer 2

draw that line... in this case the answer will be clear as soon as you draw it

Answer 3

I found the slope first which is4/0 = 0

Answer 4

Then used y-y1=m(x-x1)...........No matter what, no correct answer..

Answer 5

ok ... that is undefined.... there is no equation

Answer 6

any fraction with a 0 on the bottom is impossible

Answer 7

Okay, I put my answer as Undefined; however the teacher said it was wrong because I did not write an equation.

Answer 8

I guess I need help plugging in the correct numbers into the Point Slope Form I wrote above. I keep getting it wrong.

Answer 9

oh they want you to show your work ya gotcha....
y-y1=m(x-x1)
(2,1) and (2,5)
y-1=0(x-2)

Answer 10

ask for a regrade on that problem

Answer 11

Just curious, but I notice that in most of these examples, the y-1 always has a 1 ;however I thought we were plugging in a number from one of the points? Or is it always a 1, and then turns to just a y?

Answer 12

y1 is just a label//// it meant the first y value same with x1

Answer 13

Niel, thanks for the help

Answer 14

the answer is x=2 the slope is undefined because its a vertical line

Answer 15

I do not see how you get 2? With the formula, I get 4/0

Answer 16

Which would equal, also undefined. How do you get 2? I am seriously confused with this..

Answer 17

you have points (2,1) and (2,5)
no matter what y is, x is always 2
(2,y)
x=2

Answer 18

I got...m=(5-1) / (2-2) = 4/0 = 0

Answer 19

4/0 is undefined which indicates a vertical line plot both points on the graphand draw a line through them and it will be obvious

Answer 20

slope is rise/run
you have no run only rise

Answer 21

a slope can be undefined in the case of a vertical line its just not a function using rectangular coordinates

Answer 22

if you have a line going through (4,1) and (4,-2)
then what would you say about the line (what is the equation of this line), JJSONFIRE?

Answer 23

oh and
\[4/0\neq0\]

Answer 24

0 undefined..-3/0

Answer 25

the slope undefined so again that means you have a veritcal (|), horizontal(-), or postive(/), or negative slope(\)?

Answer 26

Okay, I understand that well now; however I am getting a little confused with writing the equations to indicate the points despite the undefined status. Teacher wants equations.

Answer 27

that is a multiple choice question above that way?
and the answer is vertical

Answer 28

Myiniaya...Vertical

Answer 29

right, both of are x's are the same (4,1) and (4,-2)
so no matter what y is x will always be 4
so the equation is x=4

Answer 30

Yes, vertical on a graph indicates it's undefined.

Answer 31

horizontal line y= n slope is 0
vertical line x= n slope is undefined
all others slope has a value that is an element of the reals as long as the \[\sqrt{-1}\] isn't involved

Answer 32

so a line going through (2,1) and (2,-5), the equation is x=2
a line going through (-5,2) and (-5,5), the equation is x=-5
a line going through (-9,0) and (-9,3), the equation is x=-9
a line going through (2,3) and (4,3), the equation is y=3
a line going through (-4,5) and (-2,5) the equation is y=5
a line going through (-1,0) and (2,0) the equation is y=0

Answer 33

in general,
a line going through (a,b) and (a,c), the equation is x=a
a line going through (g,h) and (f,h), the equation is y=h

Answer 34

all other forms use point-slope formula or slope-intercept form

Answer 35

y=h indicates a horiztonal line (slope=0)
x=a indicates a veritcal line (slope=undefined)
do you understand better?

Answer 36

Yes, \much better..thanks everyone

Answer 37

myiniaya, you've been a great big help..thanks.

Answer 38

:)