Math 8 graphing help

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AbhiKap

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Aug 23, 2012
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Hello, AbhiKap here.

I really need help on this question:

y=-2/3x+2

There is a graph given and I am supposed to graph it.

I know that you start at the 2, the y intercept, and then go down 2 and left 3. My question is: Do you start on the 2 left/right or 2 up/down.

Thanks, Help is appreciated.
 
Slope may be interpreted as RISE/RUN.

The slope in this linear equation is -2/3.

Now, here's a tip about negative signs and fractions: you can move the negative sign to three different positions, and the expression will still be -2/3.

\(\displaystyle -\dfrac{2}{3}\)

\(\displaystyle \dfrac{-2}{3}\)

\(\displaystyle \dfrac{2}{-3}\)

In other words, the negative sign can float out in front of the fraction, or it can be in the numerator, or it can be in the denominator. All three versions represent negative two-thirds.

So, if you interpret the slope as (-2)/(3), then the RISE is negative (you go down 2 units) and the RUN is positive (you go right three units).

If you interpret the slope as (2)/(-3), then the RISE is positive (you go up 2 units) and the RUN is negative (you go left three units).

Both interpretations lead to the same result. (Try both ways, and see!) :cool:
 
Last edited:
mmm4444bot said:
Slope may be interpreted as RISE/RUN.

The slope in this linear equation is -2/3.

Now, here's a tip about negative signs and fractions: you can move the negative sign to three different positions, and the expression will still be -2/3.

\(\displaystyle -\dfrac{2}{3}\)

\(\displaystyle \dfrac{-2}{3}\)

\(\displaystyle \dfrac{2}{-3}\)

In other words, the negative sign can float out in front of the fraction, or it can be in the numerator, or it can be in the denominator. All three versions represent negative two-thirds.

So, if you interpret the slope as (-2)/(3), then the RISE is negative (you go down 2 units) and the RUN is positive (you go right three units).

If you interpret the slope as (2)/(-3), then the RISE is positive (you go up 2 units) and the RUN is negative (you go left three units).

Both interpretations lead to the same result. (Try both ways, and see!) :cool:
Click to expand...

Thanks, but where exactly do you start in the graph.
 
You can start it anywhere. If you mean y= (-2/3)x+ 2 (note the parentheses- what you wrote, most people would interpret as y= -2/(3x)+ 2 but that is not a linear equation.

Yes, when = 0, y= 2 so you can start with (0, 2) on the y-axis.
I know that you start at the 2, the y intercept, and then go down 2 and left 3. My question is: Do you start on the 2 left/right or 2 up/down.
Click to expand...
?? You said "down 2 and left 3" so why mention "2 up/down"? However, slope= -2/3 can be written as either (-2)/(3) or (2)/(-3). The first would be interpreted as "down 2 and right 3" (because the -2 is negative and the 3 is positive) and the second would be interpreted as "up 2 and left 3" (because the 2 is positive and the -3 is negative). But either of those will give the same line, just going on different sides of (0, 2).
 
HallsofIvy said:
, slope= -2/3 can be written as either (-2)/(3) or (2)/(-3).
Click to expand...

And AbhiKap,

the slope can be written as any ratio of any two numbers (for example in integers),
such that the ratio = -2/3 (in this exercise).

For example, you can write it as (-4)/(6). Down 4 and right 6.

Or, for another example, you can write it as (10)/(-15). Up 10 and left 15.



And there is no requirement to move vertically first and horizontally second.


For example, (-2)/(3) can be 3 right first and then 2 down.

Or, (2)/(-3) can be 3 left first and then 2 up.
 
AbhiKap said:
Yes, but you start at 2 at the y axis correct?
Click to expand...
Perhaps there is a language problem. mmm4444bot just said "That's fine. You may start at any known point on the line." Do you understand what that means?
 
HallsofIvy said:
Perhaps there is a language problem. mmm4444bot just said "That's fine. You may start at any known point on the line." Do you understand what that means?
Click to expand...


That's fine I understand. There is no language problem as my first language is English!
 
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