If x is an integer and (x)(x^2)(x^3) is positive, which of the followi

Question

If x is an integer and (x)(x^2)(x^3) is positive, which of the following could be negative?

A. x^4 
B. (x)(x^3) 
C. (x)(x) 
D. x + x^3 
E. 3x^2

mathiaskeul · Answer

Assuming) x is negative (makes it easier)

(-2)(-2^2)(-2^3)

(-2)^3.(-2)^3

The two negative numbers will remain negative, so they will both cancel out.
So we need an equation where x^n with n being odd.

a) not sufficient -> will always be positive
b) not sufficient -> equals x^4 which will always be positive
c) not sufficient -> equals x^2 which will always be positive
d) -2+-8 = -10!!!
e) 3*4=12 is positive (pemdas!)

Answer is d

Abhishek009 · Answer

x^y can be negative only when y is odd... This x^3 will be negative Further (-ve ) + (-ve ) = (-ve ) Only (D) follows ( because all others are x^ even numbers , resulting in a +ve number)... :-D

CV7585 · Answer

If x is an integer and (x)(x^2)(x^3) is positive, which of the following could be negative?

A. x^4 
B. (x)(x^3) 
C. (x)(x) 
D. x + x^3 
E. 3x^2

A) X^4 - always positive (or 0).
B) X(X^3) = X^4 - Again always positive (or 0). 
C) (x)(x) = X^2 - Again always positive (or 0). 
D) x+x^3 - Could be -ve if x is -ve. 
E) 3X^2 - again always positive (or 0)

Answer D.

y4nkee · Answer

X is negative only when the power is odd.
Hence (d)

ehsan090 · Answer

Time Taken: 1:09
As per statement
two condition either
(-)(-)^2(-)^3=+ve
(+)(+)^2(+)^3=+ve
Now start check 
Option A: Since Power is even so always positive
Option B: Sum of Power even so always positive
Option C: Sum of power even so always Positive
Option E: Power even so always positive
For option D take -1
(-1)+(-1)^3=-2
Option: D is correct

JeffTargetTestPrep · Answer

Observe that (x)(x^2)(x^3) = x^6, which is always nonnegative regardless of the value of x. Similarly, observe that x is (or simplified to be) raised to an even power in choices A, B, C, and E, so their respective expression will also be nonnegative. Thus, the only expression that could be negative is choice D (e.g., let x = -1, then x + x^3 = -2).

Answer: D

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