Slope and Y-intercept

J

jconnors

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Oct 12, 2010
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I need to find the slope and y-intercept of 5x-8y+16=0?
Here is what I'm coming up with but I'm not sure I am doing it right?
5x-8y+16=0
5x-8y=-16
8y=-5x-16
y=-5/-8x-16/-8
y=5/8x+2

Is this correct? Any help will do, thanks.
 
Question #2
I have to graph 3x+5y=15+3x

I'm not sure on this problem either.
Here is what I've got
3x+5y=15+3x
5y=15+3x-3x
5y=15+x
y=3+1/5x

Is this correct or not?
 
jconnors said:
I need to find the slope and y-intercept

8y = -5x - 16 Typographical error; lefthand side should be -8y.

y = (-5)/(-8) x - 16/(-8)

y = 5/8 x + 2

Is this correct?

Yes, so far.

Can you finish it ?
Click to expand...
 
I need to find the slope and y-intercept

8y = -5x - 16 Typographical error; lefthand side should be -8y.

y = (-5)/(-8) x - 16/(-8)

y = 5/8 x + 2

Is this correct?

Yes, so far.

Can you finish it ?

This is as far as I need to go, I needed to find the slope (5/8) and the y-intercept (2).
 
3x + 5y = 15 + 3x

5y = 15 + 3x - 3x

3x - 3x is zero, so the next line should be:

5y = 15

So when I graph this is 0 the x axis and 3 the y axis?
 
jconnors said:
y = 5/8 x + 2

This is as far as I need to go

No, it is not. You've written only an equation; you need to answer the question.


I needed to find the slope (5/8) and the y-intercept (2)

This is correct.

Now that you've actually stated the slope and the y-intercept, you're done. 8-)
Click to expand...
 
jconnors said:
5y = 15

So when I graph this

Simplify this equation, first.

y = 3


is 0 the x axis

This question does not make sense, to me. The x-axis is never a number.

The x-axis is the Real number line, drawn horizontally through the origin. We use it to measure values of x.

and 3 the y axis? I have to guess what you're trying to ask, here.

Are you trying to ask if the y-intercept of the line is 3 ? If so, the answer is "yes".

The graph of the equation y = 3 is a horizontal line (therefore, its slope is 0) that lies three units above the x-axis. Therefore, this line crosses the y-axis at the point (0,3).
Click to expand...
 
Slope and Y - intercept calculation can be little tricky. I found this link that I use for calculating my slope stuff.. and validate my answer... maybe this is also helpful to you..


[spamming url edited out - SK]
 
Johnnyq said:
Slope and Y-intercept calculation can be little tricky.

How is that?


I found this link that I use for calculating

The calculator at that link does not really apply to the exercises in this thread. (Maybe, that's the tricky part.)

8-)

Yet, it's an interesting calculator site which includes stuff like 2010 federal tax bracket links and calorie counters, although I note that the federal link takes me to a blank .pdf document.
Click to expand...
 
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