Question 81637: I'm learning how to write my "results" in slope-intercept form. And I'm having a little difficulty trying to get these worked out and was wondering if I could get some assistance.
(0,5),m= -3/5
(-1,3) and (4,-2)
(2,-3) and (2,4)
I could really use the step by step process of how to do this, if possible. Thank you.
Answer by Edwin McCravy(20054) (Show Source):
You can put this solution on YOUR website!
I'm learning how to write my "results" in
slope-intercept form. And I'm having a little
difficulty trying to get these worked out and
was wondering if I could get some assistance.
(0,5), m =
Substitute in the point slope formula:
y - y1 = m(x - x1)
where x1 = 0 and y1 = 5
y - 5 = (x - (0) )
y - 5 = x
y = x + 5
That's the equation in the slope-intercept
form because we can compare it with
y = mx + b
and see that its slope m is and its
y-intercept (0,b) is the point (0,5)
---------------------------------------
1. (-1, 3) and (4,-2)
We first plot those two points and draw a line
through them to find out if it is vertical or
not. The equations of all lines can be placed
in slope-intercept form except the equations
for vertical lines. This is the graph we get:
We see that it is not vertical. So we can proceed
as usual:
We are to find an equation of the line containing
the points (-1,3) and (4,-2)
Use the slope formula:
y2 - y1
m = —————————
x2 - x1
where (x1, y1) = (-1,3) and (x2, y2) = (4, -2)
(-2) - (3) -5 -5
m = —————————— = ————— = ———— = -1
(4) - (-1) 4+1 5
Now substitute in the point slope formula:
y - y1 = m(x - x1)
y - 3 = (-1)(x - (-1) )
y - 3 = -(x + 1)
y - 3 = -x - 1
y = -x + 2
That's the equation in the slope-intercept
form because we can compare it with
y = mx + b
and see that its slope m is -1 and its
y-intercept (0,b) is the point (0,2)
---------------------------------------
(2,-3) and (2,4)
We plot those two points and draw a line
through them:
It is vertical, so we can't go the usual route.
Since vertical lines are the only kind of lines
which don't have slopes, there is no slope-intercept
form. But we can still write the equation. It is
simply this:
x = 2
because every point on that line has x-coordinate 2.
So x = 2 tells the story of every point on the line,
so that's all there is to the equation of that vertical
line.
Edwin
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