In the xy-plane, a line has slope 3 and x-intercept 3. What is the y-intercept of the line?
A. -9
B. -3
C. 0
D. 3
E. 9
Source:GMATPrep EP2
OA:A
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In the xy-plane, a line has slope 3 and x-intercept 3.
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Hi NandishSS,
You can deal with this prompt by either drawing a picture or by just creating an equation based on the facts that you know.
The slope-intercept formula for a line is Y = MX + B
From the prompt, we know that the slope is 3 and the X-INTERCEPT is 3 (meaning that X=3 when Y=0)
Y = MX + B
Y = 3X + B
0 = 3(3) + B
0 = 9 + B
-9 = B
So the Y-intercept is -9
Final Answer: E
GMAT assassins aren't born, they're made,
Rich
You can deal with this prompt by either drawing a picture or by just creating an equation based on the facts that you know.
The slope-intercept formula for a line is Y = MX + B
From the prompt, we know that the slope is 3 and the X-INTERCEPT is 3 (meaning that X=3 when Y=0)
Y = MX + B
Y = 3X + B
0 = 3(3) + B
0 = 9 + B
-9 = B
So the Y-intercept is -9
Final Answer: E
GMAT assassins aren't born, they're made,
Rich
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Matt@VeritasPrep
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This is easiest with the standard values for any line:
slope = m
y-int = b
x-int = -b/m
We know m = 3 and -b/m = 3. Plugging m = 3 into -b/m = 3, we get -b/3 = 3, or -b = 9, or b = -9.
b is what we wanted to find, so we're done!
slope = m
y-int = b
x-int = -b/m
We know m = 3 and -b/m = 3. Plugging m = 3 into -b/m = 3, we get -b/3 = 3, or -b = 9, or b = -9.
b is what we wanted to find, so we're done!
