Is |x| = y - z ?
(1) x + y = z
(2) x < 0
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
(1)或(2)单独都不充分,(1)+(2)sufficient!
if x>0x>0 --> y−zy−z is negative --> no good for us;
if x≤0x≤0 --> y−zy−z is positive --> good.
Two possible answers not sufficient;
(2) x