If xyz not equal to 0, is...

[SuzanR808]

If xyz not equal to 0, is (3x/2) + y + 2z = (7x/2) + y?

1) y = 3 and x = 2
2) z = -x

The book (FDP Strategy Guide #1, pg 139, Appendix A on data sufficiency) says the answer is B. I'm struggling to understand why statement 1 by itself isn't sufficient as well (making the answer D), and why it seems that the two statements contradict each other (after plugging in the numbers from statement #1).

I understand the process of rephrasing the question and getting to the simplified question statement of "is z=x?". And with that, it was easy to evaluate statement #2 from a purely logical standpoint.

However, since statement 1 does give us values for y and x, I figured that one could actually plug in those numbers into the original equation and solve for z, therefore being able to give a definitive answer to the question of whether (3x/2) + y + 2z = (7x/2) + y. When I plugged in the values for y=3 and x=2, I was able to solve for z and get -> z=2. In this case, z actually does = x (both =2), which also seems to contradict statement #2.

[RonPurewal]

However, since statement 1 does give us values for y and x, I figured that one could actually plug in those numbers into the original equation and solve for z,

there is no original equation.

the only thing in the original that looks like an "equation" is the QUESTION.
but, clearly, you can't plug into that, since the whole point of the problem is that you don't know whether that is true in the first place!

[RonPurewal]

by the way, this is the wrong folder for this question. if you have further questions, please post in the correct folder (Manhattan non-CAT math folder).

thanks.