# Is there a way to determine which solutions are extraneous without plugging them into the original equation.?

I was wondering if there is a way that you can determine which solutions of an equation are extraneous to the original equation or not, without plugging them back into the original equation.

• Yes, before you solve an equation, define the intervals were possible solutions can lie using domains and ranges of involved functions (i.e. I can look at $\sqrt{x+1}=-1$ and say that it has no solutions because a square root cannot be negative) – Vasya Mar 8 '19 at 17:31
• @Vasya: Perhaps you could convert your comment into an answer. – J W Mar 8 '19 at 17:52
• Possible duplicate of How to know if there is a extraneous solution in a radical expression – rb612 Mar 10 '19 at 8:02