Question

Which of the following inequalities matches the graph? (see attached photo)
A y _>_3x - 5
B y < 3x - 5
C y < 1/3x - 5
D The correct inequality is not listed.

Answer 1

Alright, so lets pick up where we left off. Can you find two points on the line?

Answer 2

(4,7)

Answer 3

Yup, that's one, good job.

Answer 4

@ilovenyc Can you find another one?

Answer 5

(2,8)

Answer 6

@ilovenyc Well, go over to 2 on the x axis, and then go up until you hit the line. What y are you at? That's how you get a point.

Answer 7

(2,0)?

Answer 8

@ilovenyc Not quite, although the drawing isn't too great. (2,1) is on the line.

Answer 9

Do you see how that works?

Answer 10

YES

Answer 11

Great! So now, do you remember how to find the slope?

Answer 12

To find the slope m of the line segment joining the points, use the slope formula

Answer 13

Right, so try doing that with (2,1) and (4,7)

Answer 14

@ilovenyc Making any progress, or do you need some help?

Answer 15

need some help do i add those both together?

Answer 16

Not quite, it's more of a subtraction. Here's the slope formula:

\[\frac{y_2-y_1}{x_2-x_1} \; \; \; x_1 = 2 \; \; \; x_2 = 4 \; \; \; y_1=1 \; \; \; y_2=7 \]

Answer 17

@ilovenyc So see if you can use that to find the slope. I'll be back in just a little bit.

Answer 18

@srossd so i need to subtract that

Answer 19

@ilovenyc Just use that formula I wrote, plug in the numbers. And now I'll be back in a little bit :).

Answer 20

is the answer 13?

Answer 21

No, here's another hint:

\[\frac{7-1}{4-2}\]

Answer 22

And ok, now I'm actually leaving for a little bit.

Answer 23

Just a few minutes, though.

Answer 24

@ilovenyc Alright, I'm back now. So did you get the slope from that?

Answer 25

6,and 2

Answer 26

Well, 6 divided by 2.

Answer 27

So the slope ends up being 3.

Answer 28

@ilovenyc So now you know that the line will be y=3x+b. So plug in x = 0 to that, and you'll be y=b. So look at the graph, and go to the point where x=0. Find what y is.