lpetroski wrote:
chetan2u wrote:
NoHalfMeasures wrote:
If n is an integer, is -3x^n positive?
(1) x is negative.
(2) n is odd.
pls press kudos if you liked the question
Hi,
what does the sign of -3x^n depends on ...
1) sign of x..
2) value(odd/even) of n, and not on sign of n, as it will turn the x variable in a fraction but will not effect the sign of that fraction or integer..
lets see the statements..
(1) x is negative.
we are told of one of the two things required .. insuff
(2) n is odd.
we are told of one of the two things required .. insuff
combined both the info is provided ... suff
I don't understand -- if x is negative then -3(x) = positive number and -3x^n will be positive -- is it for PEMDAS?
That x^n operation must come first?
Hi,
x^n operation is not there in PEMDAS..
because x^n is one number..
example 4=2^2 so if we have 7*2^2, it means 7*4, because 2^2 is one number..
same goes for x^n..
hence even sign of n is important..
because power of an even number will make any number positive, even if it is negative..
say x=-2 and n=2..
(-2)^2=-2*-2=4, whereas -2^3=-2*-2*-2=-8, a -ive number..
hope it helps