Hi bitenca,
This question can be solved in a couple of different ways. If you're comfortable with the 'concept' of 'slope', then you can answer this question with just a bit of arithmetic.
We're given some information about a line:
1) The line has a slope of 3/4
2) The line intersects the point (-12,-39)
We're asked at which point the line will intersect the X-axis. Since THAT co-ordinate will be (X, 0), we can use the slope to our advantage and 'count up' to that point:
With a slope of 3/4, we know that the line will "go up 3 points and go forward 4 points", meaning that the first few co-ordinates would be...
(-12,-39)
(-8, -36)
(-4, -33)
(0, -30)
Etc.
We can continue to 'count up' from here OR do a bit of algebra:
From the original co-ordinate, we know that we have to increase the '-39' to a '0' in increments of 3. That will clearly take 13 increments (since 13x3 = 39). Those same 13 increments would 'add 4' each time to the original X co-ordinate, turning '-12' into.....-12 + (13x4) = 40. Thus, the answer is (40,0).
Final Answer:
GMAT assassins aren't born, they're made,
Rich
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