Question

how would I write an equation of a line passing through the points (-2, -1) and (0, 4). Write the final answer in slope-intercept form.

Answer 1

Well first find the slope, using the following formula: \[m = \frac{ y_{2}-y _{1} }{ x _{2}-x _{1} }\] where your coordinates represent \[(x_1,y_1)~~\text{and}~~(x_2,y_2)\]
Once you manage to get that, plug in m and your first coordinates in the point - slope form: \[y-y _{1}=m(x-x _{1})\] do some little algebra and eventually you will have slope - intercept form \[y=mx+b\]

Answer 2

K thank you very much!

Answer 3

Y=2 1/2+2 does that answer look right?

Answer 4

Mhm, not quite

Answer 5

What is your slope?

Answer 6

is it Y=2 1/2+5

Answer 7

No, what happened to your x?

Answer 8

Use iambatmans steps

Answer 9

haha I did

Answer 10

Well lets do it together, step by step :), can you show me what you got for the slope?

Answer 11

2 1/2

Answer 12

Right, but lets stick to 5/2

Answer 13

ok so now lets use point slope form, can you show me how you would do it

Answer 14

y-y1=m(x-x1)

Answer 15

Yeah, so plug in y1, x1 and m into the equation, leave y and x alone

Answer 16

\[y+1=5/2 (x+2)\] right? And we want y = mx+b

Answer 17

y-(-1)=2 ½(x+2)

Answer 18

Yeah, that's fine, now we just do some algebra :)

Answer 19

so distribute 5/2 over (x+2) and then move +1 to the right! And we're done

Answer 20

Y=5/2x+6

Answer 21

Subtract -1 not add :P

Answer 22

But good job!

Answer 23

K thanks a lot for the help!

Answer 24

HI!!

Answer 25

No problem :)

Answer 26

did you get the slope?

Answer 27

you already have the y intercept

Answer 28

the points (-2, -1) and (0, 4)...
since the point \((0,4)\) is on the graph, the y intercept is \(4\)

Answer 29

Yes, that's right, we could always use that to check our answer! :)

Answer 30

?

Answer 31

no checking involved
find \(m\) and write
\[y=mx+4\]

Answer 32

Yes, I know but it's good to use other methods and seeing what's going on as well.

Answer 33

haha sorry but you guys' are confusing me:]

Answer 34

Don't worry about it haha, you can use any method, I usually prefer using what misty said after you understand the above method :P

Answer 35

As you get used to point slope form and slope intercept and see a relationship between them, it's pretty neat actually.

Answer 36

K thanks!

Answer 37

Np, thank you Misty :)