commonsense27 wrote:I still stand by my answer. If book is saying otherwise, book needs to be corrected.
We should use our fundamentals to arrive at a choice. If everytime we change our fundamentals based on the question, we will be in deep shit.
This is an exponential problem. There is absolutely nothing wrong that I am doing.
Square root cancels the square. And
X^0=1 as long as the x !=0.
ANSWER IS 1.
No, sqrt(x^2) is *not* always equal to x. You can see this by plugging in x = -2, say. Then sqrt(x^2) = sqrt(4) = 2, which is not equal to x; it's equal to -x. In general, sqrt(x^2) is *always* equal to |x|, but it is only equal to x if x is zero or greater.
When learning a mathematical rule, it's important to learn when you are allowed to apply it, and when you are not. The rule you are trying to use here, that (x^a)^b = x^(ab), is *not* always true if x is negative. If you don't want to take my word for it, you can read the 'Real powers of positive numbers' section here:
en.wikipedia.org/wiki/Exponentiation#Identities_and_properties
The GMAT does this all the time - tests if you understand the exceptions to the familiar algebraic rules you have learned. Often it's just as important to know when you *can't* apply a rule as it is to know when you can.