Mathematics
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OpenStudy (anonymous):
thanks
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OpenStudy (anonymous):
y = -x + 8
So we have m = -1 and b can be anything
y = -x + b II y = -x + 8
y = -1 x = 4
-1 = -4 +b
b= 3
OpenStudy (welshfella):
x+y=8
y = -x + 8
this has a slope of -1
OpenStudy (anonymous):
no?
OpenStudy (anonymous):
I think is y = -x + 3
Directrix (directrix):
y - y1 = m* (x - x1) where (x1,y1) = (4, -1) and m = -1
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Directrix (directrix):
Parallel lines have the same slope.
OpenStudy (welshfella):
yes This form is called the Point-slope form of a straight ;ime
Directrix (directrix):
y - (-1) = 1* (x - 4)
OpenStudy (anonymous):
u could also use\[y=mx+b\]where\[y=vertical~axis\]\[x=horizontal~axis\]\[m=slope\]\[b=constant/y-intercept\]
Directrix (directrix):
Why not finish this first: y - (-1) = 1* (x - 4)
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OpenStudy (anonymous):
y=x-5
OpenStudy (anonymous):
go ahead @Directrix :)
Directrix (directrix):
Yeah, well, I have a bad slope.
y - y1 = m* (x - x1) where (x1,y1) = (4, -1) and m = -1
y - (-1) = -1* (x - 4)
OpenStudy (anonymous):
y = -x + 5 (4;-1)
-1 = -4 + 5
3 = 5?????? I can not undertand you
OpenStudy (anonymous):
\[(4,-1)=(x,y)\]\[m=-1\]substitute this value into this equation to find b\[y=mx+c\]
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OpenStudy (anonymous):
\[y=mx+b*\]
OpenStudy (anonymous):
we have
y = kx + c
OpenStudy (anonymous):
\[-1=-1(4)+b\]\[-1=-4+b\]Add 4 on both sides
OpenStudy (anonymous):
\[-1+4=-4+4+b\]\[b=3\]
OpenStudy (anonymous):
YES
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OpenStudy (anonymous):
y = -x + 8
So we have m = -1 and b can be anything
y = -x + b II y = -x + 8
y = -1 x = 4
-1 = -4 +b
b= 3
in the top of this question
OpenStudy (anonymous):
\[Now,we~can~form~a~new~equation~using\]\[m=-1~and~b=3\]substitute this value to form the equation\[y=mx+b\]
Directrix (directrix):
y = -x + 3
OpenStudy (anonymous):
yep :)
OpenStudy (anonymous):
T_T
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OpenStudy (anonymous):
thanks guys so much!!!
Directrix (directrix):
It's fun when several people collaborate in a thread.
OpenStudy (anonymous):
It was strange
OpenStudy (anonymous):
Agree @Directrix
yw! @cutegirl