SOLUTION: Write an equation for a line that passes through the following points: (-7, 9), (8, 9) I dont really know how to do this, and i would really apperciate seeing the steps that ex

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Question 162368: Write an equation for a line that passes through the following points:
(-7, 9), (8, 9)
I dont really know how to do this, and i would really apperciate seeing the steps that explain how to do this problem. THank you in advance!
Found 2 solutions by josmiceli, gonzo:
Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website!
Remember that each point is an (x,y) that completely satisfies
the equation.
The general equation for a line is .
You can plug in the x and y for each point and then
solve for m and b. You don't even have to know what
m and b are to do this
The points are (-7,9) and (8,9)

(1)
(2)
Now subtract (2) from (1), being careful of signs

If in either (1) or (2), then

Now write an equation for the line using the facts

This is the equation of the line. It is a horizontal line
where y is always and x can be anything in either
the (+) or (-) direction.
You can practice this method. Just pick any two points
and do what I did.

Answer by gonzo(654) (Show Source):
You can put this solution on YOUR website!
let (x,y) = (-7,9)
let (x1,y1) = (8,9)
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you need the slope intercept form of the equation for a straight line.
that is:
y = m*x + b
where m is the slope and b is the y intercept.
y intercept is the value of y when x equals 0
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first you solve for m which is the slope.
the formula for the slope is (y-y1)/(x-x1)
substituting from above, you get (9-9)/(-7-8) = 0/-15 = 0.
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right off the bat it looks like you are going to have a horizontal line since the slope is 0.
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now that you have the slope, you need to find the y intercept.
take one of the points and substitute it in the slope intercept form of the equation with m = 0
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that equation is
y = 0*x + b
substitute x = -7 and y = 9
you get
9 = 0*(-7) + b
which becomes
b = 9.
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your complete equation is y = 0*x + 9
which reduces to y = 9
-----
graph of that equation is a horizontal line with y = 9 for any value of x.
graph shows up below