jscott319 wrote:

Is x^2 greater than x?

(1) x^2 is greater than 1

(2) x is greater than -1

I was doing this question and did not particularly like the explanation that was given. Was my approach of rephrasing this question appropriate?

I rephrased it this way:

x^2 > x

x^2 - x > 0

x(x-1) > 0

Then from this i deduced that both of those phrases would have to be either positive or both would have to be negative. I felt that statement 1) allowed me to determine that but statement 2) did not. Was my approach correct?

jscott319 wrote:

Is x^2 greater than x?

(1) x^2 is greater than 1

(2) x is greater than -1

This question has more to do with DECIMAL PROPERTIES than actual inequality

(1) x^2 is greater than 1

x^2 is always greater than 1 except for two cases

i) x^2 is EQUAL to 0 When x is 0

ii) x^2 is LESS than x when x is a decimal between -1 and 1

example -0.60^2 = 0.36 (0.36 < 1)

example 0.40^2 = 0.16 (0.16 < 1)

But since here x^2 is greater than 1 we know that x is not a decimal between -1 to 1

Any other value of x (-ve or +ve) will always be smaller than its square ; therefore x^2 > x

SUFFICIENT

(2) x is greater than -1 [/quote]

x can be 0 and 0^2 is NOT > 0

x can be 4 and 4^2 > 0

INSUFFICIENT

ANSWER IS A

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