Yeah, I found it.

So, there is no typo in your post but as I said there is no x that satisfies the equation. (GMAT doesn't deal with complex numbers).

When I decided to test the question? Hm... I often "play" with numbers before solving a problem. Sometimes it helps to find a shortcut.

Let's forget about this particular question. I guess I got what your problem is.

Suppose we have the equation: a = b. Can we say that a^2 = b^2? Yeah, it's correct. Now, let's take a look at an example:

-\sqrt{x} = 2(-\sqrt{x})^2 = 2^2x = 4Is it right? No. Because

-\sqrt{4} = -2 \neq 2. So, a solution of a^2=b^2 isn't necessarily a solution of a = b and it's important to check it out. So, x=4 is a correct solution of

(-\sqrt{x})^2 = 2^2 but it's not a solution of

-\sqrt{x} = 2.

Hope it helps

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