Question

решите примеры, буду очень благодарен!​

Answer 1

1)

$( - \sqrt{5} )^{2} + 4 \sqrt{49} - \sqrt{121} = 5 + 4 \times 7 + - 11 = 22$

$(1 + \sqrt{2} )(2 + 3 \sqrt{2} ) = 2 + 3\sqrt{2} + 2 \sqrt{2} + 3 \times 2 = 8 + 5 \sqrt{2}$

$( \sqrt{5} - \sqrt{2} ) \sqrt{5} + 3 \sqrt{2} = 5 - \sqrt{10} + 3 \sqrt{2}$

2)

$\sqrt{16x} + \sqrt{9x} + \sqrt{100x} = 4 \sqrt{x} + 3 \sqrt{x} - 10 \sqrt{x} = - 3 \sqrt{x}$

3)

$\frac{21}{3 \sqrt{7} } = \frac{7}{ \sqrt{7} } = \sqrt{7}^{2} \div \sqrt{7} = \sqrt{7}$

$\frac{ \sqrt{12} + \sqrt{18} }{ \sqrt{2} + \sqrt{3} } = \frac{ \sqrt{6}( \sqrt{2} + \sqrt{3}) }{\sqrt{2} + \sqrt{3}} = \sqrt{6}$

4)

$\frac{5}{ \sqrt{x} } = \frac{5 \sqrt{x} }{x}$

$\frac{x^{2} - 3 }{x - \sqrt{3} } = \frac{(x - \sqrt{3})(x + \sqrt{3}) }{x - \sqrt{3} } = x + \sqrt{3}$

$\frac{21}{2 \sqrt{2} + 1 } = \frac{21(2 \sqrt{2 } - 1) }{(2 \sqrt{2} + 1)(2 \sqrt{2} - 1) } = \frac{21(2 \sqrt{2} - 1) }{8 - 1} = 3(2 \sqrt{2} + 1) = 6 \sqrt{2} + 3$