每日一题

Mathematics>Standard Multiple Choice

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

If y=((x+1)*(x-2))/((x+3)*(x-4)), for which of the following values of x is y NOT defined?

(A) -4
(B) -3
(C) -1
(D) 2
(E) 3

答案和解析

答案：B

解析：

Division by 0 is not defined, so y=((x+1)*(x-2))/((x+3)*(x-4)) is not defined when (x+3)*(x-4)=0. The product (x+3)*(x-4) is equal to 0 if x=-3 or if x=4. Therefore, y is defined for all of the choices except -3.