Question

\(\left(2\sqrt{8}+3\sqrt{5}-7\sqrt{2}\right)\left(\sqrt{72}-5\sqrt{20}-2\sqrt{2}\right)\)tính, ghi rõ các bước giải

Answer 1

​\(=\left(4\sqrt{2}+3\sqrt{5}-7\sqrt{2}\right)\left(6\sqrt{2}-10\sqrt{5}-2\sqrt{2}\right)\)

\(=\left(-3\sqrt{2}+3\sqrt{5}\right)\left(4\sqrt{2}-10\sqrt{5}\right)\)

\(=-24+30\sqrt{10}+12\sqrt{10}-150\)

\(=-174+42\sqrt{10}\)

Answer 2

= ( 4√2 + 3 √5 - 7√2 ) ( 6√2 - 10√5 - 2√2)

= ( -3√2 + 3√5 ) ( 4√2 - 10√5 )

= -24 + 30√10 + 12√10 - 150

= - 174 + 42√10