a)

Skoro $x^2=100$ i $x\ge 0$, to $x=10$, bo $10^2=100$.

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b)

Skoro $x^2=81$ i $x\ge 0$, to $x=9$, bo $9^2=81$.

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c)

Skoro $x^2=6\frac{1}{4}=\frac{25}{4}$ i $x\ge 0$, to $x=\frac{5}{2}$, bo ${\left(\frac{5}{2}\right)}^2=\frac{25}{4}$.

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d)

Skoro $x^2=0$ i $x\ge 0$, to $x=0$, bo $0^2=0$.

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e)

Skoro $x^2=\frac{9}{49}$ i $x\ge 0$, to $x=\frac{3}{7}$, bo ${\left(\frac{3}{7}\right)}^2=\frac{9}{49}$.

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f)

Skoro $x^2=0,01$ i $x\ge 0$, to $x=0,1$, bo ${\left(0,1\right)}^2=0,01$.

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g)

Skoro $x^2=121$ i $x\ge 0$, to $x=11$, bo $11^2=121$.

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h)

Skoro $x^2=225$ i $x\ge 0$, to $x=15$, bo $15^2=225$.