Bunuel wrote:
Is |x^7|*y^3*z^4>0
(1) xy < 0
(2) yz > 0
Kudos for a correct solution.
|x^7|*y^3*z^4>0?
|x^7| will always be positive due to the absolute value
z^4 will always be positive due to the even power
y^3 could be negative (a 'no' to the question) or positive (a 'yes' to the question)
Rephrased, we are looking to see if y is positive or negative.
Is y positive or negative?
Statement 1:
x is negative and y is negative OR
x is positive and y is positive
Insufficient
Statement 2:
y is negative and z is negative OR
y is positive and z is positive
Insufficient
Combined, y could be positive or negative. Still insufficient to answer the question.
Answer: E