b)
[tex]4-100x^{2} =0\\4=100x^{2} /:100\\\frac{1}{25} =x^{2} /\sqrt[2]{} \\[/tex]
[tex]x=\frac{1}{5}[/tex] v [tex]x=-\frac{1}{5}[/tex]
c)
[tex]4x^{2} -121=0\\4x^{2} =121/:4\\x^{2} =\frac{121}{4} /\sqrt[2]{} \\[/tex]
[tex]x=\frac{11}{2}[/tex] v [tex]x=-\frac{11}{2}[/tex]
Pozdrawiam.
