I need help writing an equation in point-slope form for the line through the given point with the given slope (-4, -2); m=-1/2 I think the answer is either y-2 = -1/2 (x-4) or y+2 = -1/2(x-4) ??

Question

I need help writing an equation in point-slope form for the line through the given point with the given slope (-4, -2); m=-1/2   I think the answer is either y-2 = -1/2 (x-4) or y+2 = -1/2(x-4) ??

freckles · Answer

point slope form is
y-y1=m(x-x1)
where (x1,y1) is the point given
and m is the slope

freckles · Answer

you are given m is -1/2
so you did good there

freckles · Answer

you are given x1 is -4 and y1 is -2

freckles · Answer

so if you put those in then you have 
y-(-2)=-1/2 (x-(-4)) correct?

freckles · Answer

but you can simplify that a little

freckles · Answer

since -*-=+

anonymous · Answer

Ok

anonymous · Answer

That is where I was confused on if it was minus 2 or +2

freckles · Answer

but you understand now
that if you have a -*- you have a +

anonymous · Answer

Yes.

anonymous · Answer

Can you help me with one more?

freckles · Answer

ok one more

anonymous · Answer

(5, -6); m=-0.38   I think it is y+6=-0.38(x+5)

freckles · Answer

ok well again point slope form is 
y-y1=m(x-x1)
everything is right except for your x1

freckles · Answer

x1=5

freckles · Answer

not -5

anonymous · Answer

wait didn't I say y + 6 = -0.38(x+5)?

freckles · Answer

yes but you said x was 5

freckles · Answer

but you entered in -5

freckles · Answer

$$y-y_1=m(x-x_1) \ (x_1,y_1)=(5,-6) \text{ and } m=-0.38 \ y-(-6)=-0.38(x-5)$$

anonymous · Answer

Okay! Thanks so very much!

freckles · Answer

examples:
$$(1,1) ; y-1=m(x-1) \ (1,-1);y-(-1)=m(x-1) \ (-1,1); y-1=m(x-(-1)) \ (-1,-1); y-(-1)=m(x-(-1)) \ \text{ simplifying } \ (1,1); y-1=m(x-1) \ (1,-1); y+1=m(x-1) \ (-1,1); y-1=m(x+1) \ (-1,-1); y+1=m(x+1)$$

freckles · Answer

I guess if it really confuses you
think opposite when plugging into the point slope form
so if x=1 then I will x-1
and if i have x=-1 then I will have x+1
and if I have y=1 then I will have y-1
and if I have y=-1 then I will have y+1
but the only thing about this
is if you memorize this it might also make other things more confusing in the future

freckles · Answer

so if I have the point (7,-4) with slope -2
then I have
y+4=-2(x-7)

anonymous · Answer

Okay, but that did help. I wont memorize it! I don't like math, it is very much like a foreign language!!!

freckles · Answer

i bet one day you will be all giggly to do math

anonymous · Answer

lol I doubt it! :))

anonymous · Answer

Thank You for your help! Have a Merry Christmas! :)

freckles · Answer

Happy Holidays to you as well.