SOLUTION: What is the slope intercept form of (2,1) (-5,-8)?

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Question 1069958: What is the slope intercept form of (2,1) (-5,-8)?
Found 2 solutions by Fombitz, rothauserc:
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
First find the slope,
m=%28-8-1%29%2F%28-5-2%29
Then use a point and the slope to find the x-intercept,
y=mx%2Bb
1=m%282%29%2Bb
2m%2Bb=1
b=1-2m
So then,
y=mx%2Bb

Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
the slope of a line through two points is defined as
:
slope(m) = (y(2) - y(1)) / (x(2) - x(1))
:
let (2, 1) be (x(1), y(1)) and ((-5, -8) be (x(2), y(2))
:
m = (-8 - 1) / (-5 - 2) = -9 / -7 = (9 / 7)
:
so far we have
:
y = 9x/7 + b
:
we can use either point, so lets pick (x(1), y(1))
:
1 = (9(2)/7) + b
:
b = 1 - (18/7) = (7/7) - (18/7) = (-11/7)
:
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slope intercept form is y = (9x/7) - (11/7)
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