xy coordinate line

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Source: — Data Sufficiency |

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by rohu27 » Wed Feb 16, 2011 8:53 am
is it a GMAT prep question by any chance?
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by earnest10 » Wed Feb 16, 2011 11:36 am
rohu27 wrote:is it a GMAT prep question by any chance?
earnest10 wrote:Image
Yes ... it is

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by VivianKerr » Wed Feb 16, 2011 11:53 am
Here's my thinking:

y = 3x + 2 contain (r,s)?
- yes/no question
- sufficiency determined if we know the value of BOTH r AND s.

(1) (3r + 2 - s)(4r + 9 - s) = 0

One equation with both r and s in it. We cannot solve for the variables individually.

(2) (4r - 6 - s)(3r + 2 - s) = 0

Same issue - one equation with two variables.

If we combine the statements, we have 2 equations with the same 2 variables. Should be suff.
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by Night reader » Wed Feb 16, 2011 4:04 pm
Hello my friend, function is like equation
In the xy plane does the line with equation y = 3x + 2 contain the point ( r , s) ?

1. ( 3r+2-s)(4r+9-s) = 0.
2. (4r-6-s)(3r+2-s) =0.
y is s and x is r, now rewrite everything --> s=3r+2 OR 3r+2-s=0 :) /I know you smile too

st(1) BECOMES ridiculously simple ( 3r+2-s)(4r+9-s) = 0 is Not Sufficient, because we have also (4r+9-s) can be 0
st(2) heh, (4r-6-s)(3r+2-s) =0; you know everything here --> (3r+2-s) =0 ? Not Sufficient

may be Combined ? st(1&2): both ( 3r+2-s)(4r+9-s) = 0 AND (4r-6-s)(3r+2-s) =0 can be zero if one of common factors is 0 (zero). Only possible with the ( 3r+2-s) = 0 why not Sufficient?

IOM C
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