Question

2a²-5ab+2b² при a=√7 +√6 и b =√7 -√6​

Answer 1

Ответ:

47

Объяснение:

2a²-5ab+2b²

$2(\sqrt{7} -\sqrt{6} )^2 -5 (\sqrt{7} -\sqrt{6})(\sqrt{7}+\sqrt{6}) +2 (\sqrt{7} +\sqrt{6} )^2 = 2(7-2\sqrt{42} +6) -5(7-6) +2(7+2\sqrt{42} +6) = 2(13-2\sqrt{42} ) -5 +2(13+2\sqrt{42} ) = 26-4\sqrt{42} -5 +26+4\sqrt{42} = 47$