Question

Calcule o valor de cada expressão
$a) \: \sqrt{6} \times ( \sqrt{15} \ + \sqrt{60} ) \\ \\ b) \: \sqrt{3} \: \times ( \sqrt{54} \: - \sqrt{6}) \\ \\ c)( \sqrt{3} - 1)( \sqrt{3} + 1) \\ \\ d)(2 - \sqrt{2} )(2 + \sqrt{2} )$
Me ajude por favor.
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Answer 1

a) $\sqrt{6}. (\sqrt{15}+\sqrt{60})=\sqrt{6}.(\sqrt{15}+2\sqrt{15})=\sqrt{6}.3\sqrt{15}=3\sqrt{90}=9\sqrt{10}$

b) $\sqrt{3}.(\sqrt{54}-\sqrt{6})=\sqrt{3}.(3\sqrt{6}-\sqrt{6})=\sqrt{3}.2\sqrt{6}=2\sqrt{18}=6\sqrt{2}$

c) $(\sqrt{3}-1)(\sqrt{3}+1)=\sqrt{3^2}-1^2=3-1=2$

d) $(2-\sqrt{2})(2+\sqrt{2})=2^2-\sqrt{2}^2=4-2=2$