Question

How do I find the equation of a line that passes through (-2,-1) and (-1, -6)? I have to put it in slope intercept form

Answer 1

\[\large y = mx+b\]

m = slope
b = y-intercept

Answer 2

First, I suggest you to figure out the slope.

Answer 3

Do you know how to?

Answer 4

the slope is -5

Answer 5

Okay so we will go with that.

Answer 6

Now that we have the slope as -5, we can substitute m for that.

\[\large y = -5x + b\]

Usually, in this case, what I would do is choose a coordinate from the two that are already given. So we will use (-2,-1)...

As you can see that with -5 there is a "x". We will substitute that x with -2 and the y before the equal sign will be replaced with the y-coordinate (or -1).
\[\large -1 = -5(-2) + b\]

Now you need to solve for b.

Answer 7

So I'm multiplying -5 and -2 and that gives me 10

Answer 8

yes go on...

Answer 9

I don't know how to solve for b...I don't know what to do next

Answer 10

\[\large -1 = 10 + b\]
\[\large -1 - 10 = 10 - 10 + b\]
\[\large -11 = b\]

Let's check this now:
\[\large -1 = -5(-2) - 11 => -1 = 10 - 11 => -1 = -1\]

Answer 11

\[\large -6 = -5(-1) -11 => -6 = 5 - 11 => -6 = -6\]

Answer 12

So your slope intercept form is
\[\large y = -5x - 11\]

Answer 13

Do you understand how I got it? @llroberts43

Answer 14

sorry I'm at work...trying to get off the phone so I can look

Answer 15

Ok, you subtracted 10 from both sides and that gave you the -11

Answer 16

yes

Answer 17

we needed to isolate b

Answer 18

Thank you. I have a final on this stuff today and I'm just stressed out. I don't remember doing this stuff

Answer 19

It's okay .. take a deep breath and you will be fine..

just review the work that I did in here.

Answer 20

I will. thanks again