Răspuns :
(√12 + √15 ) ·√3 = √12√3 + √15√3 = √36 + √9√5 = 6 + 3√5
(√5 ) · ( 3√5 + 5√8) = 3√5√5 + 5√5√8 = 3√25 + 5√5√4√2 = 3·5 + 5·2√10 =
= 15 +10√10
(√5 ) · ( 3√5 + 5√8) = 3√5√5 + 5√5√8 = 3√25 + 5√5√4√2 = 3·5 + 5·2√10 =
= 15 +10√10
[tex]( \sqrt{12} + \sqrt{15} ) \cdot \sqrt{3} = \sqrt{12 \cdot 3} + \sqrt{15 \cdot 3} = \sqrt{36} + \sqrt{45} =6+3 \sqrt{5} \\ \sqrt{5} \cdot (3 \sqrt{5} +5 \sqrt{8} )=3 \cdot 5+5 \sqrt{40} =15+5 \cdot 2 \sqrt{10} =15+10 \sqrt{10} [/tex]