GMATPrepNow wrote:
Line J: 4x - 7 = 6y
Line K: 6y + 3x = -2
Line L: 2x = 5 - y
In the x-y coordinate plane, lines J, K and L are defined by the above equations.
Point B is the point of intersection of lines J and K. Point C is the point of intersection of lines K and L.
What is the slope of line segment BC?
A) -3/2
B) -2/3
C) -1/2
D) 1/2
E) 2/3
Great question...
Answer is right there staring at you if you understand itA point, B ,is at intersection of line J and K and another point, C, is at intersection of K and L..
so points B and C are on line KWhen you join B and C, it is nothing but a part of line K..
So slope will be same as that of line K..
\(6y+3x=-2........6y=-3x-2......y=-\frac{3x}{6} -\frac{2}{6}\)
Slope is \(-\frac{3}{6}=\frac{-1}{2}\)
C
Also if you do not get this, other way is..
Take lines J and K
Line J: 4x - 7 = 6y
Line K: 6y + 3x = -2
Two equation two variables, so you will get value of X and y of B
Similarly of C from line K and L..
Slope will be \(\frac{y_B-y_C}{x_B-x_C}\)
You will get answer as -1/2
C
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