GMATPrep Coordinate Geometry - another confusing question

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Source: — Data Sufficiency |

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by sasha79 » Thu Sep 11, 2008 1:23 pm
IMO D

Explanation:

from (1), we get:
3r+2-s =0
4r+9-2=0

solving for r and s gives us: r=-7 and s=-19

plugging these values for x and y in the equation gives us:
(-19) = 3(-7) +2
(-19) = (-19)
therefore, (1) is sufficient to determine that point (r,s) is on the line with equation y=3x+2

Similarly, from (2) you can solve for r and s like above and plug in the values into the equation.

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by chandu822 » Sat Sep 13, 2008 7:38 am
Its a two variable problem.

Think of it this way:

If (1-x)(1-y) = 0 we dont say 1-x = 0 and 1-y =0

Similarly in this problem we cant find r,s with nither condition.1 or 2

However considering both 1 and 2 together will certainly help.

Hence answer is C