每日一题

Mathematics>Standard Multiple Choice

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

The function f is graphed in the x y-plane above. If the function g is defined by g（x） = f（x） + 4, for how many values of x between -5 and 15 does g（x）equal 0?

(A) None
(B) One
(C) Two
(D) Three
(E) More than three

答案和解析

答案：C

解析：

The graph of the function g is the same as the graph of the function f translated up 4 units. The function f intersects the x-axis three times, but if the graph is shifted up 4 units, then the graph will intersect the x-axis only twice. Therefore, g(x) is equal to 0 for exactly two values of x between -5 and 15.