DS question from the prep, please shed some light on the pro

[aimhier]

Dear instructors，i have a DS question from the prep, please shed some light on the problem

If x^2 does not equal 1, does x^2+1 = a/{x^2 - 1} ?

1) x^4 = a+1

2) x<0

the OA is A, but what if a=0, then there's no way for the equation to be valide

[RonPurewal]

Dear instructors，i have a DS question from the prep, please shed some light on the problem

If x^2 does not equal 1, does x^2+1 = a/{x^2 - 1} ?

1) x^4 = a+1

2) x<0

the OA is A, but what if a=0, then there's no way for the equation to be valide

In statement 1, it's impossible for "a" to be zero.
If you try to make that happen, then you'll get x^4 = 0 + 1 = 1, and thus x^2 is also 1. That violates the stated condition at the beginning of the problem.