Resposta :
Temos que:
[tex]9\text{x}^2-49=0[/tex]
Isolando o [tex]\text{x}^2[/tex]:
[tex]\text{x}^2=\dfrac{49}{9}[/tex]
[tex]\text{x}=\pm\sqrt{\dfrac{49}{9}}=\pm\dfrac{7}{3}[/tex]
Logo, [tex]\text{S}=\{\pm\frac{7}{3}\}[/tex]
olá!!!
Basta vc isolár o X²
[tex]9x^2-49=0[/tex]
[tex]9x^2=49[/tex]
[tex]x^2=\frac{49}{9}[/tex]
[tex]x=\±\sqrt{\frac{49}{9}}[/tex]
[tex]x=\±\frac{7}{3}
[tex]\Large{\boxed{x=\{-\frac{7}{3},\frac{7}{3}\}}}[/tex]
espero ter ajudado