I recently saw this equation online.
(X + 1)^ 4 = 81
It was solved in the following fashion
1. X + 1 = (81)^ (1/4)
2. X + 1 = 3
3. X = 2
The site said Step 1. was wrong. Can anyone explain why exactly?
Step 1 isn't so much wrong as incomplete. There is an additional solution, namely -(81)^(1/4)
(-3)^4 = 81 as well as 3^4 = 81
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