In the xy-coordinate plane, line A is defined by the equation j*x-y=-7

Hi All,

We're told that In the XY-coordinate plane, line A is defined by the equation (J)(X) - Y = -7 and line B is defined by the equation 3X + 2Y = K and that the two lines are NOT parallel. We're asked at what point they intersect. to start, with graphing questions, it usually helps to convert the given equations into slope-intercept format (re: Y = MX + B). In this case, the lines would be:

Y = (J)(X) + 7
Y = 3x/2 + K/2

We have to figure out at what point will X and Y be the same for BOTH equations.

1) Line A passes through the point (3,1)

With the co-ordinate in Fact 1, we can plug in and get....

1 = J(3) + 7
-6 = 3J
-2 = J

Now our two equations are:
Y = -2X + 7
Y = 3X/2 + K/2

Unfortunately, we still have an unknown (K) and that keeps us from figuring out where the lines intersect.
Fact 1 is INSUFFICIENT

2) Line B passes through the point (0,7)

With the co-ordinate in Fact 2, we can plug in and get....
7 = 0 + K/2
K = 14

Now, the two lines are;
Y = 3X/2 + 7
Y = (J)(X) + 7

Notice how the y-intercepts are the same in both equations? We now KNOW where the two lines intersect: at (0,7)
Fact 2 is SUFFICIENT

Final Answer:

GMAT assassins aren't born, they're made,
Rich