Помогите пожалуйста!!!

?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)
$formula \: \: \: {(a + b)}^{2} = {a}^{2} + 2ab + {b}^{2} \\ - - - - - - - - - - \\ {( \sqrt{3} + \sqrt{27} )}^{2} - 18 = {( \sqrt{3}) }^{2} + 2 \sqrt{ 3 \times {3}^{2} \times 3 } + {( \sqrt{27} )}^{2} - 18 = 3 + 2 \times 3 \times 3 + 27 - 18 = 30 + 18 - 18 = 30$