If ax + b = 0, is x > 0 ?
(1) a + b > 0
(2) a - b > 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.
見題,在不考慮限制條件下,x可為正數、負數和0。
考慮條件1:if b=0, a>0, 則因為ax+b=0,所以x必須為0,存在例外,(A)錯誤
考慮條件2:同上例子,則x必為0,(B)錯誤。
一個例子同時符合兩個條件:C、D錯誤
選E