from the prompt we have : |x| = y-2z / 5

....no we don't. You've fallen into a common trap here:

The equation in the question is not an equation that is given as true. Instead, it is an equation whose truth the question is asking you to evaluate. In other words, the question is: Is the left hand side equal to the right hand side?

In your work, you have assumed that the left hand side does equal the right hand side (even though that is the very question we are supposed to answer!)

OHH THANKS a LOT.

IMO E

wat is OA....

andy123 wrote:Hi Please tell me why is the answer not B ?


q) Is 5|x| = y - 2z?

5x + y = 2z
x < 0

My question is why is (2) not sufficient alone ?

from the prompt we have : |x| = y-2z / 5

so either x > 0 , then x = ( y-2z ) / 5

or x <0

then x = - { (y -2z) / 5 }
= 2z-y / 5 ??

Choose C.
q) Is 5|x| = y - 2z?
This means whether 5x = y- 2z when x>0
or whether -5x = y - 2z when x<0

St1] 5x + y = 2z. This confirms one part of the 2nd possible outcome above, but we do not whether x> 0.
St2] x < 0. Insuff by itself.
Together the 2nd outcome above is fully met.

IMO A. after solving stmt2 we get -5x= y-2z
or 5|x|=y-2z

sufficient to prove the question. We do not need to kno whether x<0 or x>0 .


Correct me if I am wrong

You replaced -5x with 5|x|, but you can do so only if |x| = -x , i.e. x < 0

If x > 0, -5|x| = -5x