graphing

Pete

New member
Joined
Jan 17, 2006
Messages
8
Hi,

I have just started to learn this subject so I am a little lost.

I understand the y intercept and b=0,3 would be on the y axis, up 3

I also understand that 3/5x means that you go up 3 from the "b" position and to the right 5.

What doesnt make sense to me is how you would graph -3/5. I keep thinking that both numbers are negative so you go down and left. Im sure im totally out of it so any help or "rules" would be greatly appreaciated
 
-3/5 = 3/-5

But watch that -3/-5 = 3/5

Draw these out.

If the slope is \(\displaystyle \mbox{ \frac{rise}{run} = \frac{-3}{5}}\), go down 3 (the 'rise' is -3) and to the right 5 (the 'run' is +5) and mark the point. Draw the line through this point and the y-intercept.

If the slope is \(\displaystyle \mbox{ \frac{rise}{run} = \frac{3}{-5}\), go up 3 (the 'rise' is +3) and to the left 5 (the 'run' is -5) and mark the point. Draw a line through this point and the y-intercept.

They're the same line, aren't they?
 
So you are saying that if the fraction is negative I can just make either the numerator or the denominator the negative and move just the one number left or down as the case may be.
 
Pete said:
So you are saying that if the fraction is negative I can just make either the numerator or the denominator the negative and move just the one number left or down as the case may be.


you got it! And as you see now, two negative moves (down, left) = +.
 
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