Question

3.Sa se calculeze:
a)$2 \sqrt{8}$+$2 \sqrt{8}+5 \sqrt{32} + 4 \sqrt{2}=$
b)$6 \sqrt{3}-2 \sqrt{27}+5 \sqrt{6}: \sqrt{2}$=
c)$\sqrt{20}-12 \sqrt{5}+ \sqrt{45} =$=
d)$5 \sqrt{18}+ \sqrt{12}-3 \sqrt{20}+ \sqrt{72}+ \sqrt{45}$=
e)$3( \sqrt{20}+ \sqrt{45})- \sqrt{125}=$
Dau cel mai bun raspuns.

Answer 1

$a).2 \sqrt{8}+2 \sqrt{8} +5 \sqrt{32} +4 \sqrt{2} =4 \sqrt{2} +4 \sqrt{2} +20 \sqrt{2} +4 \sqrt{2} =32 \sqrt{2} \\ b).6 \sqrt{3} -2 \sqrt{27} +5 \sqrt{6} : \sqrt{2} =6 \sqrt{3} -6 \sqrt{3} +5 \sqrt{3} =5 \sqrt{3} \\ c). \sqrt{20} -12 \sqrt{5} + \sqrt{45} =2 \sqrt{5} -12 \sqrt{5} +3 \sqrt{5} =-7 \sqrt{5}$
$d).5 \sqrt{18} + \sqrt{12} -3 \sqrt{20} + \sqrt{72} + \sqrt{45} = \\ =15 \sqrt{2} +2 \sqrt{3} -6 \sqrt{5} +6 \sqrt{2} +3 \sqrt{5} =21 \sqrt{2} +2 \sqrt{3} -3 \sqrt{5} \\ e).3( \sqrt{20} + \sqrt{45} )- \sqrt{125} =3(2 \sqrt{5} +3 \sqrt{5} )-5 \sqrt{5} = \\ =3 \cdot 5 \sqrt{5} -5 \sqrt{5} =15 \sqrt{5} -5 \sqrt{5} =10 \sqrt{5}$