Question

what does this mean ?? am i supposed to make a graph ?
Which of the following sets of points do not fit into a line?
{(-7,-1),(-5,1),(-1,5),(0,6)} {(2,1), (-2,4), (2,5), (-1,4)}
{(-2,-4),(0,-2),(3,1),(7,5)} {(-5,1),(-2,-2),(0,-4),(1,-5)}

Answer 1

No, you don't need to make a graph to figure this one out.

Answer 2

You should be able to tell by slopes.

Answer 3

for any line other than a perfectly vertical line, for any value of x there will be only one value of y. Are there any sets of points here that do not satisfy that rule?

Answer 4

Austin, you dolt... vertical line test... *facepalm*
listen to palmer.

Answer 5

@austinL you could find the slopes, it'd just be a lot more work, because you'd have to try it between most of the pairs of points :-)

Answer 6

Well, actually... You can tell which ones cannot be a function with the vertical line test... but which ones are actually a "line" is different isn't it.

Answer 7

yeah, but if one of your candidates fails the vertical line test (and isn't otherwise a vertical line), then you don't need to worry about the others...

Answer 8

but how do i find which one doesn't fit into the line ?

Answer 9

Okay, here's the reasoning:

One of the sets of points has two x values the same, but with different y values. The only way that can happen is if you have a vertical line (same value of x, all y values different). However, it doesn't have ALL the same values of x, just some of them. That means it looks something like my drawing:

Answer 10

so would it be {(-5,1),(-2,-2),(0,-4),(1,-5)/

Answer 11

No, do you see any pairs there where the x value is the same? remember, it's (x,y)

Answer 12

As you can see from my graph, those points all fall on a line: