<PRE><B>Question 162368</B>
let (x,y) = (-7,9)
let (x1,y1) = (8,9)
-----
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
-----
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.
-----
right off the bat it looks like you are going to have a horizontal line since the slope is 0.
-----
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
-----
that equation is
y = 0*x + b
substitute x = -7 and y = 9
you get
9 = 0*(-7) + b
which becomes
b = 9.
-----
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
{{{graph(400,400,-5,5,-1,10,9)}}}

</PRE>