Question

Помогите пожалуйста!!!

Answer 1

▪1.

$3 sqrt{12} - 0.1 sqrt{300} - sqrt{48} = 3 sqrt{ {2}^{2} times 3} - 0.1 sqrt{ {10}^{2} times 3} - sqrt{ {4}^{2} times 3} = 6 sqrt{3} - sqrt{3} - 4 sqrt{3} = sqrt{3}$
такого варианта ответа нет.
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▪2.

$sqrt{28b} - 2 sqrt{112b} + sqrt{63b} = sqrt{ {2}^{2} times 7b } - 2 sqrt{ {4}^{2} times 7b } + sqrt{ {3}^{2} times 7b } = 2 sqrt{7b} - 8 sqrt{7b} + 3 sqrt{7b} = - 3 sqrt{7b}$
и такого варианта ответа нет.
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▪3.
а)
$formula : : {(a - b)}^{2} = {a}^{2} - 2ab + {b}^{2} \ - - - - - - - - - - - - \ {( sqrt{m} - sqrt{n}) }^{2} = { sqrt{m} }^{2} - 2 sqrt{mn} + { sqrt{n} }^{2}$
б)
$formula : : (a - b)(a + b) = {a}^{2} - {b}^{2} \ - - - - - - - - - - - - \ ( sqrt{3} - 7)( sqrt{3} + 7) = { sqrt{3} }^{2} - {7}^{2} = 3 - 49 = - 46$
в)
$formula : : : (a - b)(a + b) = {a}^{2} - {b}^{2} \ - - - - - - - - - - - - - - - - - - \ ( sqrt{13} + 6 sqrt{2} )(6 sqrt{2} - sqrt{13} ) = {(6 sqrt{2} )}^{2} - { (sqrt{13} )}^{2} = 36 times 2 - 13 = 72 - 13 = 59$
г)
$formula : : : {(a + b)}^{2} = {a}^{2} + 2ab + {b}^{2} \ - - - - - - - - - - \ {( sqrt{3} + sqrt{27} )}^{2} - 18 = {( sqrt{3}) }^{2} + 2 sqrt{ 3 times {3}^{2} times 3 } + {( sqrt{27} )}^{2} - 18 = 3 + 2 times 3 times 3 + 27 - 18 = 30 + 18 - 18 = 30$