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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2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html

3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html

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