9. Is n<0?
(1) -n=|-n|
if -n = |-n| then -n must be positive as it is equal to an absolute value. Therefore, -n = |-n| ===> -(-n) = |-n|
N CAN BE ≥0 AS -(-0) = |-0| ===> 0=0!
INSUFFICIENT
(2) n^2=16
|n| = 4
n=4 OR n=-4
N could be less than zero or greater than zero.
INSUFFICIENT
1+2) #1 tells us that N is ≥0. #2 tells us that n could be 4 or -4. The only value of n that is ≥0 is 4.
SUFFICIENT
(C)
(1) -n=|-n|
if -n = |-n| then -n must be positive as it is equal to an absolute value. Therefore, -n = |-n| ===> -(-n) = |-n|
N CAN BE ≥0 AS -(-0) = |-0| ===> 0=0!
INSUFFICIENT
(2) n^2=16
|n| = 4
n=4 OR n=-4
N could be less than zero or greater than zero.
INSUFFICIENT
1+2) #1 tells us that N is ≥0. #2 tells us that n could be 4 or -4. The only value of n that is ≥0 is 4.
SUFFICIENT
(C)