Write the equation of a trend line.
{(-15,8), (-8,7), (-3,0), (0,0), (7,-3)}

@hlambach

Question

Write the equation of a trend line. 
{(-15,8), (-8,7), (-3,0), (0,0), (7,-3)}




@hlambach

hlambach · Answer

Try graphing it first. Plot the points and connect them.

hlambach · Answer

Naw, don't do that never mind, haha.

anonymous · Answer

Awww it will take so long! is there any way we can speed it up?

hlambach · Answer

Yeah, don't do it.

anonymous · Answer

lol! :D

hlambach · Answer

This will be a straight line, right?

anonymous · Answer

Im not sure, will it? :P

hlambach · Answer

Wait, no, it's not because it is a trend line.

anonymous · Answer

okay.. not to be rude, but I have to turn this in in 20 mins and ll have 4 questions left. please just this time help me with the answers please this will make or break my grade!

hlambach · Answer

Okay, so you want to find a slope-intercept equation.

anonymous · Answer

Are you sure? hey you have 56 not 55 now! :)

hlambach · Answer

So find the slope of two points using the formula $$(y _{2}-y _{1})/x _{2}-x _{1})$$

hlambach · Answer

Yay! haha

anonymous · Answer

could you find the answer while i brb? i have to attend my grandma

hlambach · Answer

I don't have a calculator with me...

hlambach · Answer

I have to leave in like ten minutes. After that, just plug in a point in the equation and find b.

anonymous · Answer

okay i am back.. no you're leaving??? please finish this last one for me!!

hlambach · Answer

Do what I said and you got it.

hlambach · Answer

Pick any two points, find the slope, then plug in the slope and a point in the equation
y=mx+b

anonymous · Answer

okay... could you help?

hlambach · Answer

Yeah. But try it first.

anonymous · Answer

okay i pick 0,0.

hlambach · Answer

Now pick another one and find the slope using the formula I gave you earlier.

anonymous · Answer

okay.. i pick 7, -3
0- 7 is 0 and 0 - -3 is 3

hlambach · Answer

0-7=-7

anonymous · Answer

how?

anonymous · Answer

have 7 apples take away 0 still have 7

hlambach · Answer

(0-(-3))/(0-7) is how you find teh slope.

hlambach · Answer

But you put the zero in front.

anonymous · Answer

-0.428571429 but i have to write an equation of a trend line

hlambach · Answer

I know, I know. Now see if your calculator can make that into a fraction

anonymous · Answer

how?

hlambach · Answer

usually it's a button that looks like this f->d or d->f

anonymous · Answer

it says the number i entered was too small

hlambach · Answer

Oh wait, -7/3 is a fraction haha. So that is your slope

anonymous · Answer

okay how do i find the equation for a trend line? because that is what i need

hlambach · Answer

Okay, so now that you have a slope for equation, just put in a point in the equation
y=-7/3x+b and find b

anonymous · Answer

oops sorry

anonymous · Answer

y=-7/3x+(-8,7)
now what

hlambach · Answer

No, put in 7 for y and -8 for x

hlambach · Answer

In the formula I gave you.

anonymous · Answer

-8 - 7 is 1

hlambach · Answer

Is that what b equals? If yes, then you have your formula.

anonymous · Answer

i think so, am i right?

anonymous · Answer

y=-7/3x+1?

hlambach · Answer

yup

anonymous · Answer

awesome! do you have to go?

hlambach · Answer

Yeah.

anonymous · Answer

okay thanks for all the help

hlambach · Answer

No problem. Thanks for all the medals!

anonymous · Answer

of course! maybe later you could help more!