Question

scoateti factorii de sub radi cal si aduceti expresia la o forma mai simpla
$a)0.4 \sqrt{12 } - 0.9\sqrt{27} + 1.3 \sqrt{75} \\ b)- 2 \sqrt{80} - 10 \sqrt{189} - 12 \sqrt{1029} + 2 \sqrt{525}$
$c) \sqrt{0.8} + \sqrt{3.2} + \sqrt{5} - 10 \sqrt{7.2}$
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Answer 1

$a)0,4\sqrt{12}-0,9\sqrt{27}+1,3\sqrt{75}=\\ \\ \frac{4}{10} *2\sqrt{3}-\frac{9}{10} *3\sqrt{3}+\frac{13}{10} *5\sqrt{3}=\\ \\ \frac{8\sqrt{3}-27\sqrt{3}+65\sqrt{3}}{10}=\frac{46\sqrt{3}}{10}=\frac{23\sqrt{3}}{5}.$

$b)-2\sqrt{80}-10\sqrt{189}+12\sqrt{1029}+2\sqrt{525}=\\ \\ -2*4\sqrt{5}-10*3\sqrt{21}+12*7\sqrt{21}+2*5\sqrt{21}=\\ \\ -8\sqrt{5}+64\sqrt{21}=-8*(\sqrt{5}-8\sqrt{21}).$

$c)\sqrt{0,8}+\sqrt{3,2}+\sqrt{5}-10\sqrt{7,2}=\\ \\ \sqrt{\frac{8}{10}}+\sqrt{\frac{32}{10}}+\sqrt{5}-10\sqrt{\frac{72}{10}}=\\ \\ \frac{\sqrt{8}+\sqrt{32}-\sqrt{7200}}{\sqrt{10}}+\sqrt{5}=\\ \\ \frac{2\sqrt{2}+4\sqrt{2}-60\sqrt{2}}{\sqrt{10}}+\sqrt{5}=\\ \\ \frac{-54\sqrt{2}}{\sqrt{10}} +\sqrt{5}=\frac{-54}{\sqrt{5}}+\sqrt{5} =\frac{-54+5}{\sqrt{5}} =-\frac{49\sqrt{5}}{5} .$

@robertinnifd