Which of the following CANNOT be a value of x when y = x/(x-1) ? (A) -2 (B) -1 (C) 0 (D) 1/3 (E) 1 OA is E

As the denominator of the expression on the right-hand contains (x - 1), x cannot be equal to 1 as that will make y = 1/0 which is indeterminate. Answer : E

The denominator can never equal zero!

"Fun" follow-up question: Which of the following CANNOT be a value of y when y = x/(x-1) ? (identify all correct answers) (A) -2 (B) -1 (C) 0 (D) 1/3 (E) 1 (F) -1 Cheers, Brent

Brent@GMATPrepNow wrote:Which of the following CANNOT be a value of y when y = x/(x-1) ? x > (x - 1) Now, if (x - 1) > 0, i.e. x > 1 ---> x/(x - 1) > 1 And, if (x - 1) x/(x - 1) < 1 So, x/(x - 1) can never be equal to 1. Answer : E

Atekihcan wrote:Brent@GMATPrepNow wrote:Which of the following CANNOT be a value of y when y = x/(x-1) ? x > (x - 1) Now, if (x - 1) > 0, i.e. x > 1 ---> x/(x - 1) > 1 And, if (x - 1) x/(x - 1) < 1 So, x/(x - 1) can never be equal to 1. Answer : E Good stuff. Another approach is to recognize that, in order for x/(x-1) to equal one, the numerator must equal the denominator. Since it's impossible for x to equal x-1, the expression can never equal 1. Aside: I added the bit about identifying all correct answers to see if anyone would bite and select F as well. Cheers, Brent

Brent@GMATPrepNow wrote:Another approach is to recognize that, in order for x/(x-1) to equal zero... You meant to say 'one', I guess. Brent@GMATPrepNow wrote:Aside: I added the bit about identifying all correct answers to see if anyone would bite and select F as well. B and F are same answer choice.

Atekihcan wrote:Brent@GMATPrepNow wrote:Another approach is to recognize that, in order for x/(x-1) to equal zero... You meant to say 'one', I guess. Good catch. I edited it accordingly Brent@GMATPrepNow wrote:Aside: I added the bit about identifying all correct answers to see if anyone would bite and select F as well. B and F are same answer choice. Another nice catch! I guess I should have another cup of coffee Cheers, Brent