Resposta:
a) [tex]S = \{-5,5\}[/tex]
b) [tex]S = \{-3,3\}[/tex]
c) [tex]S = \{-3,3\}[/tex]
d) [tex]S = \{-\frac{4}{3},\frac{4}{3}\}[/tex]
Explicação passo a passo:
a)
[tex]x^2 - 25 = 0\\x^2 = 25\\\sqrt{x^2} = \sqrt{25}\\x = \pm5\\S = \{-5,5\}[/tex]
b)
[tex]2x^2 - 18 = 0\\2x^2 = 18\\x^2 = \frac{18}{2}\\x^2 = 9\\\sqrt{x^2} = \sqrt{9}\\x = \pm 3\\S = \{-3,3\}[/tex]
c)
[tex]4x^2 = 36\\x^2 = \frac{36}{4}\\x^2 = 9\\\sqrt{x^2} = \sqrt{9}\\x = \pm 3\\S = \{-3,3\}[/tex]
d)
[tex]9x^2 = 16\\x^2 = \frac{16}{9}\\\sqrt{x^2} = \sqrt{\frac{16}{9}}\\x = \pm \frac{4}{3}\\S = \{-\frac{4}{3},\frac{4}{3}\}[/tex]
