Question

Rezolvari in R ecuatiile:
|x+1|+|x-1|=0

x din cel deal doilea modul este la puterea a 2-a dar nu am putut pune...

Answer 1

|x+1|+|x^2-1|=0 <=> |x+1|+|(x+1)(x-1)|=0 <=> |x+1|+|x+1|*|x-1|=0 <=> |x+1|*(1+|x-1|)=0.
Cum 1+|x-1|>=1>0, obtinem ca |x+1|=0 adica x+1=0 adica x=-1.