Question

Which of the following is the reciprocal of x^2 – 2x – 8?

A. (x + 2)(x - 4)
B. 1/(x + 2)(x - 4)
C. 1/x - 8
D. 1/x + 2

Answer 1

Factor,(x + 2)(x - 4)

Answer 2

Then take the inverse or reciprocal of the factor .Sam. has posted and this should give you the answer B.

Answer 3

either use hit and trial method i.e. for eg . at x =1,,f(x)=-9..that option will be correct which yields -1/9..this is option B ..otherwise you can use the orthodox method..split -2x into -4x + 2x and take common and factorize..