Bunuel wrote:

If \(y^{-2} + 2y^{-1} -15 = 0\), which of the following could be the value of y?

A. \(3\)

B. \(\frac{1}{5}\)

C \(\frac{-1}{5}\)

D. \(\frac{-1}{3}\)

E. \(-5\)

Let \(y^{-1}=x\)

So, \(y^{-2} + 2y^{-1} -15 = 0\)

Or, \(x^2+2x-15=0\)

Or, x=-5 or x=3

1. x=-5, or, \(y^{-1}=-5\) or, \(y=\frac{-1}{5}\)

2. x=3,or, \(y^{-1}=3\) or, \(y=\frac{1}{3}\)

Among given options, correct answer is (C)[/quote]

P.S:- Already discussed .

https://gmatclub.com/forum/if-y-2-2y-1- ... 69804.html
_________________

Regards,

PKN

Rise above the storm, you will find sunshine