a)

Obliczamy:

$6^2-8^2=6\cdot 6-8\cdot 8=36-64=-28$

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b)

Obliczamy:

${\left(6-8\right)}^2={\left(-2\right)}^2=\left(-2\right)\cdot \left(-2\right)=4$

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c)

Obliczamy:

${\left(-10\right)}^2-{\left(-7\right)}^2=\left(-10\right)\cdot \left(-10\right)-\left(-7\right)\cdot \left(-7\right)=100-49=51$

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d)

Obliczamy:

${\left(-10-\left(-7\right)\right)}^2={\left(-10+7\right)}^2={\left(-3\right)}^2=\left(-3\right)\cdot \left(-3\right)=9$

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e)

Obliczamy:

$1^3-3^3=1\cdot 1\cdot 1-3\cdot 3\cdot 3=1-27=-26$

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f)

Obliczamy:

${\left(1-3\right)}^3={\left(-2\right)}^3=\left(-2\right)\cdot \left(-2\right)\cdot \left(-2\right)=-8$