GMATPrep Test 1 #2_PS #2

[kwah]

What is the most efficient way to achieve the result for the question attached?

Answer: E

Thanks,
K

[Jim@StratusPrep]

simplify first to this:

xy +z = xy + xz

then

z = xz

when is this true?

both sides will be 0 if z = 0 or

both sides will be z if x = 1