Question

os numeros -1 e 1 sao raizes de quais dessas equaçoes :

A-)x²-1=0
B-)-X²+1=1
C-)X-1=0
D-)-X²-1=0
E-)X²-1=0
F-)-X²+1=0

Answer 1

Vamos calcular

$a) \\ x^{2} -1=0 \\ x^{2} =1 \\ x=\pm \sqrt{1} \\ x=\pm1 \\ \\ S=\{-1,+1)~~\mapsto confere \\ \\ b) \\ - x^{2} +1=1 \\ - x^{2} =1-1 \\ - x^{2} =0 \\ x^{2} =0 \\ x= \sqrt{0} \\ x=0~~\mapsto n\tilde{a}o~~confere \\ \\ c) \\ x-1= \\ x=1~~\mapsto n\tilde{a}o~~confere \\ \\ d) \\ - x^{2} -1=0 \\ - x^{2} =1~~~\times(-1) \\ x^{2} =-1 \\ x=\pm \sqrt{-1} ~~n/~existe~~raiz~~negativa~~\in~~R \\ \\ e) \\ x^{2} -1=0 \\ x^{2} =1 \\ x=\pm \sqrt{1} \\ x=\pm1~~confere$ 

$f) \\ - x^{2} +1=0 \\ - x^{2} =-1~~\times(-1) \\ x^{2} =1 \\ x=\pm \sqrt{1} \\ x=\pm1~~~confere \\ \\ Resposta: A,E,F$