giúp mình rút gọn đc ko
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\(=\left(\sqrt{5}-\sqrt{3}\right).\sqrt{2}.\sqrt{8-\sqrt{15}}\)
\(=\left(\sqrt{5}-\sqrt{3}\right).\sqrt{16-2\sqrt{15}}\)
\(=\left(\sqrt{5}-\sqrt{3}\right)\sqrt{15-2\sqrt{15}+1}\)
\(=\left(\sqrt{5}-\sqrt{3}\right)\sqrt{\left(\sqrt{15}-1\right)^2}\)
\(=\left(\sqrt{5}-\sqrt{3}\right)\left|\sqrt{15}-1\right|\)\(=\left(\sqrt{5}-\sqrt{3}\right)\left(\sqrt{15}-1\right)=5\sqrt{3}-\sqrt{5}-3\sqrt{5}+\sqrt{3}\)
\(=6\sqrt{3}-4\sqrt{5}\)
Vậy...
\(\left(\sqrt{10}-\sqrt{6}\right)\sqrt{8-\sqrt[]{15}}\)
\(=\sqrt{2}\left(\sqrt{5}-\sqrt{3}\right)\sqrt{8-\sqrt{15}}\)
\(=\sqrt{16-2\sqrt{15}}.\left(\sqrt{5}-\sqrt{3}\right)=\sqrt{\left(\sqrt{15}-1\right)^2}\left(\sqrt{5}-\sqrt{3}\right)\)
\(=\left(\sqrt{15}-1\right)\left(\sqrt{5}-\sqrt{3}\right)=5\sqrt{3}-3\sqrt{5}-\sqrt{5}+\sqrt{3}=6\sqrt{3}-4\sqrt{5}\)
Trả lời
\(\frac{21}{39}\)
\(=\frac{21:3}{39:3}\)
\(=\frac{7}{13}\)
Study well
1125/55 =225/11 ;
362/62 =181/31 ;
762/657 =219/254
; 768/900 =64/75
hết buồn nha!!! k nhé.
\(x\inƯ\left(63\right)\)
\(Ư\left(63\right)=\left\{1;3;7;9;21;63\right\}\)
\(x+1\inƯ\left(63\right)\Rightarrow x=1-1=0\)
\(x=3-2=1\)
\(x=7-1=6\)
\(x=9-8=1\)
\(x=21-1=20\)
\(x=63-1=62\)
\(\Rightarrow x\in\left\{0;2;6;8;20;62\right\}\)
đk : x khác -2 ; 2
\(\dfrac{2}{x+2}+\dfrac{x}{x-2}-\dfrac{x^2+4}{x^2-4}\)
\(=\dfrac{2x-4+x^2+2x-x^2-4}{x^2-4}=\dfrac{4x-8}{x^2-4}=\dfrac{4}{x+2}\)