[tex]a) \: \sqrt{x } =3 \sqrt{7} [/tex]
[tex]x = 9 \times 7[/tex]
[tex]x = 63[/tex]
[tex] \sqrt{63} = 3 \sqrt{7} [/tex]
[tex]3 \sqrt{7 } = 3 \sqrt{7} [/tex]
[tex]x =6 3[/tex]
[tex]b) \: \sqrt{x {}^{2} } = 4[/tex]
[tex] |x| = 4[/tex]
[tex]x1 = - 4[/tex]
[tex]x2 = 4[/tex]
[tex]c) \: x {}^{2} = 27 [/tex]
[tex]x = ± 3 \sqrt{3} [/tex]
[tex]x1 = - 3 \sqrt{3} [/tex]
[tex]x2 = 3 \sqrt{3} [/tex]
[tex]d) \: (2x + 1) {}^{2} = 25 [/tex]
[tex]2x + 1 = ± 5[/tex]
[tex]2x + 1 = - 5[/tex]
[tex]2x + 1 = 5[/tex]
[tex]x1 = - 3[/tex]
[tex]x2 = 2[/tex]
