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Question 455711: The question asks to find the y intercept and slope of the line that represents the table. The table looks likes this..
Time (min) | 5 | 10 | 15 | 20 | 25 |
Charge.($) | 8 | 13 | 18 | 23 | 28 |
I found the slope, but I do not understand how to find the y-intercept
Answer by Edwin McCravy(20060) (Show Source):
You can put this solution on YOUR website!
Time (min) | 5 | 10 | 15 | 20 | 25 |
Charge ($) | 8 | 13 | 18 | 23 | 28 |
I'll show you three ways to find it.
Plot the 5 points on a graph:
Draw a line through them
Now you can see that the green line crosses the y-axis at 3,
That means the y-intercept is the point (0,3).
Another way to do it is to look at your list:
Time (min) | 5 | 10 | 15 | 20 | 25 |
Charge ($) | 8 | 13 | 18 | 23 | 28 |
Notice that the times are spaced out in steps of 5 minutes
starting with 5
Also notice that the charges are spaced out is steps of 5,
starting with 8.
Now suppose we wanted to put in a point before (5,8). It
would have to be (0,3)
Time (min) | 0 | 5 | 10 | 15 | 20 | 25 |
Charge.($) | 3 | 8 | 13 | 18 | 23 | 28 |
That's because the point before the first one would have to be
gotten by subtracting 5 from 5 getting 0 and 5 from 8 getting 3.
So the y-intercept is (0,3)
You can also do it by first finding the slope using the first two
points, (5,8) and (10,13) and then using the point-slope form.
Now the y-intercept is gotten by substituting x=0
So the y-intercept is (0,3).
Edwin
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