In the rectangular quadrant system shown...
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In the rectangular quadrant system shown above, which quadrant, if any, contains no point (x, y) that satisfies the equation 3x + 5y = -2?
A. none
B. I
C. II
D. III
E. IV
The OA is B.
I need to re-write the equation of the following form,
$$y=-\frac{3}{5}x-\frac{2}{5}$$
Now I can draw the line and get the solution for this PS question, right?
I appreciate if any expert explain it for me. Thank you so much.
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- Brent@GMATPrepNow
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One option is to use some number sense.
Notice that for two values (x and y), to satisfy the equation 3x + 5y = -2, at least one of the values (x or y) must be NEGATIVE.
Conversely, we should recognize that x and y cannot both be POSITIVE
Otherwise we have the equation 3(POSITIVE) + 5(POSITIVE) = -2, which is impossible.
If x and y cannot both be POSITIVE, (x,y) cannot be in quadrant I, since all points in quadrant I are such that the x and y coordinates are both POSITIVE
Answer: B
Cheers,
Brent
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- Brent@GMATPrepNow
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Yes, that's a great approach.AAPL wrote: I need to re-write the equation of the following form,
$$y=-\frac{3}{5}x-\frac{2}{5}$$
Now I can draw the line and get the solution for this PS question, right?
Now you know that the y-intercept is -2/5 AND the slope is negative.
When you sketch the graph, you'll see that the line does NOT pass through quadrant I
Cheers,
Brent