$a\text{)}3x^2=0\mid :3$  

$x^2=0$  

$x=0$  

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$b\text{)}{x}^2-9=0$  

$x^2=9\mid \sqrt{}$  

$x_1=3\text{lub}{x}_2=-3$  

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$c\text{)}{x}^2=121\mid \sqrt{}$  

$x_1=11\text{lub}{x}_2=-11$  

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$d\text{)}-2x^2-8=0$  

$-2x^2=8\mid :\left(-2\right)$  

$x^2=-4$  

to równanie nie ma rozwiązania

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$e\text{)}{x}^2-3=0$  

$x^2=3$  

$x_1=\sqrt{3}\text{lub}{x}_2=-\sqrt{3}$  

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$f\text{)}{x}^2-\frac{4}{25}=0$  

$x^2=\frac{4}{25}\mid \sqrt{}$  

$x_1=\frac{2}{5}\text{lub}{x}_2=-\frac{2}{5}$  

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$g\text{)}5x^2=99-6x^2\mid +6x^2$  

$11x^2=99\mid :11$  

$x^2=9\mid \sqrt{}$  

$x_1=3\text{lub}{x}_2=-3$  

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$h\text{)}\left(x+5\right)\left(x-5\right)=24$  

$x^2-5x+5x-25=24$  

$x^2-25=24\mid +25$  

$x^2=49\mid \sqrt{}$  

$x_1=7\text{lub}{x}_2=-7$  

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$i\text{)}{x}^2+169=0\mid -169$  

$x^2=-169$  

to równanie nie ma rozwiązania

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$j\text{)}{x}^2-12x=2{\left(x-3\right)}^2$  

$x^2-12x=2\cdot \left(x^2-6x+9\right)$  

$x^2-12x=2x^2-12x+18$  

$x^2=-18$  

to równanie nie ma rozwiązania

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$k\text{)}{\left(x-4\right)}^2=9-8x$  

$x^2-8x+16=9-8x$  

$x^2+16=9\mid -16$  

$x^2=-7$  

to równanie nie ma rozwiązania

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$l\text{)}{\left(y+3\right)}^2=3\left(2y+6\right)$   $y^2+6y+9=6y+18\mid -6y$ $y^2+9=18\mid -9$  

$y^2=9$  

$y_1=3\text{lub}{y}_2=-3$