GWD5-20

[Emilyh]

Q20:
Lines k and m are parallel to each other. Is the slope of line k positive?
(1) Line k passes through the point (3, 2).
(2) Line m passes through the point (-3, 2).

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.

Ans :E

可以幫忙解這題嗎?

謝謝

[FrankChang]

km兩平行線斜率是否為正?!
(1)只知道(3,2)是k線上一點,如果要再平面上取另一個通過k的點,
會產生無限多種斜率,
(想像把若(3,2)當作圓心,直徑是不是可以轉個360度..)
斜率從0到正負無限大都有可能.
(2)亦然
(1)&(2)兩條平行線各自可以通過(3,2)(-3,2)產生無限種斜率
我想汽車雨刷可以更容易讓你想像.