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Question 70625: Can you please help on this problem, rather complicated...instructions..write the equation of the line passing through (5,5) and (4,5).
Found 2 solutions by bucky, venugopalramana:
Answer by bucky(2189)   (Show Source):
You can put this solution on YOUR website! This is a "trick" question, so you need to be a little careful with it. It usually is
helpful to make a rough sketch of the x and y-axes and then plot the points, just to help
visualize the slope of the line. Then we could proceed to use the slope-intercept form of an
equation ... y = mx + b ... where m is the slope and b is the point at which the graph crosses
the y-axis.
.
But in this case something unusual happens when you try to calculate the slope.
.
For the two given points (5,5) and (4,5) you can identify the first point as (x1,y1).
And you can identify the second point as (x2,y2). By comparing each given point to its
corresponding form you can see that: x1=5, y1=5, x2=4, and y2=5. Now write the equation for
finding the slope (m) if you know two points on the line. This equation is:
.
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Now plug in the values for x1, y1, x2, and y2. When you do the slope equation becomes:
.
.
But look at the numerator. 5 minus 5 is zero. The denominator equals -1. And when you
divide -1 into zero, the answer is zero. What does a slope equal to zero mean? If a line
has a slope of zero, it does not go upward or downward. It just stays horizontal.
.
So the graph is a horizontal line. It has the same value for y regardless of the value
for x. If you think about it a little bit, for this problem you will see that the line
goes across the y-axis at +5 and it runs in both directions as far as you want. Whatever
value you chose for x, y is always +5 units above the x-axis. And the equation for this
situation is y = +5. That's your answer ... choose any value on the x-axis and the corresponding
value of y is always +5.
.
Think about it a little bit and it will make sense. Also your sketch would have shown you
that the line was probably horizontal and then you could have verified that by using the
slope equation.
Answer by venugopalramana(3286)  (Show Source):
You can put this solution on YOUR website! Can you please help on this problem, rather complicated...instructions..write the equation of the line passing through (x1,y1)=(5,5) and (x2,y2)=(4,5).
eqn. is given by
y-y1=[(y2-y1)/(x2-x1)][x-x1]
y-5=[(5-5)/(4-5)][x-5]=0
y=5
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