SAT试题类型:Mathematics > Standard Multiple Choice

Read the following SAT test question and then click on a button to select your answer.

In the xy-plane, line l passes through the points (a, 0) and (0, 2a), where a > 1.  What is the slope of line l?

(A) -2
(B) -0.5
(C) 2
(D) -2a
(E) 2a

答案:A

解析:

Explanation

Choice (A) is correct. Given two points on a line, the slope of the line can be found by dividing the change in the y-coordinates between the points by the corresponding change in the x-coordinates. Hence, since line l passes through the points (a, 0) and (0, 2a), its slope is