Question

I've got an ACT question that I am really confused with.
http://imgur.com/FY9p1
The correct answer is C.
I understand how C works but I dont understand how E doesnt work. Please help :(

Answer 1

I think we might have ourselves an error here. ;-p

\[\huge x^{-2}> y^{-2} \Rightarrow \frac{1}{x^2} > \frac{1}{y^2}\]

So for a counterexample, let x and y have the same absolute value (x = 2, y = -2 or x = 3, y = -3, etc...)

Then \[\huge \frac{1}{(3)^2}> \frac{1}{(-3)^2} \text{ is false! (they are equal)}\]

E is not always true.

Answer 2

E doesn't always work...
suppose x=3, y=-2... E would be false in this case.

Answer 3

Thanks for the help guys, I see why its not E.
For the y^-2
I was trying to plug in #'s for x and y to see if E was true. I was putting in values for y in my calculator without the parentheses and getting negative numbers.
Its A really mean question for ACT to throw at us.