Question

What is an equation of the line?
https://snag.gy/FajMlQ
^The graph
A. y+3=2(x+2)
B. y+5=1/2(x+2)
C. y-3=1/2(x-2)
D. y+3=-2(x-2)

Answer 1

what do you think?

Answer 2

No clue

Answer 3

I also have 1 more question

Answer 4

k, gimme a sec to figure out the first one :)

Answer 5

ok, have you tried to substitute some point to the equations to see which one it is?

Answer 6

No haha sorry. Its fine

Answer 7

There are two points on the graph, do you know what they are?

Answer 8

Two points: ( -2, -3 ) and ( 2, 5 )

Answer 9

Now find the slope using \[m = \frac{ y _{2}-y _{1} }{ x _{2}-x _{1} }\]

Answer 10

Lemme know if you are stuck.

Answer 11

Thank you :D

Answer 12

Did you find the slope using the formula?

Answer 13

Uhm one moment

Answer 14

Well wait
How do you know which point is 1 and how do you know the other is 2?

Answer 15

The black dots on the graph

Answer 16

Look at the point ( - 2 , -3 ) is at, you see black dot yes?

Answer 17

Yeah like which is x1 is it -2 or 2?

Answer 18

Either points work, you will get the same answer

Answer 19

Oh okay so then wait one second and I'll work it out

Answer 20

So far I have y(3)-y(5/x(-2)-x(2)

Answer 21

Version #1
\[m = \frac{ -3 - 5 }{ -2 - 2 } = \frac{ - 8 }{ -4 } = 2\]

Version #2
\[m = \frac{ 5 - ( -3) }{ 2 - (-2) } = \frac{ 8 }{ 4 } = 2\]

Answer 22

2 is your slope

Answer 23

Ohh thanks for brakeing that down for me I see it is the same

Answer 24

thats I got too

Answer 25

Are you familiar with the point-slope form?

Answer 26

No well maybe

Answer 27

\[y - y _{1} = m ( x - x _{1})\]
That is the point-slope form.

Answer 28

Oh okay

Answer 29

Now, use of the points, ( - 2 , - 3) and slope 2. Then, simply plug in the information into the point-slope equation. There is your equation :)

Answer 30

One moment

Answer 31

m = 2?

Answer 32

cause if so its: 3-5=2(-2-2)

Answer 33

the 'y' and the 'x" are variables, you don't substitute into them. Only the y1 and x1

Answer 34

Oh I understand that.

Answer 35

Thank you VERY much

Answer 36

no problemo :)

Answer 37

Oh that's fine let me change it haha. Perfect explaining

Answer 38

using point: ( - 2 , - 3) and m = 2
\[y - ( - 3) = 2 [ x - ( - 2 ) ] \]
\[y + 3 = 2 ( x + 2)\]

Answer 39

Yes That makes sense

Answer 40

Then if you change it into intercept form y = mx + b

Answer 41

y + 3 = 2x + 4
y = 2x + 4 - 3
y = 2x + 1

Answer 42

On the graph, you see it intersects the y-axis at ( 0 , 1 ) and that the slope moves up two and one to the right forming the line.