[tex]a) \: \: \: a = ( \frac{20}{ \sqrt{1800} } - \frac{3}{ \sqrt{72} } ) \div \frac{1}{84} \\ a = ( \frac{20}{30 \sqrt{2} } - \frac{3}{6 \sqrt{2} } ) \times \frac{84}{1} \\ a = (\frac{2}{3 \sqrt{2} } - \frac{1}{2 \sqrt{2} } ) \times \frac{84}{1} \\ a = \frac{4 - 3}{6 \sqrt{2} } \times \frac{84}{1} \\ a = \frac{14}{ \sqrt{2} } = 7 \sqrt{2} \\ \\ \\ b = ( \sqrt{3} - 3) {}^{2} - \sqrt{( \sqrt{3} - 2) {}^{2} } + \sqrt{75} \\ b = 3 - 6 \sqrt{3} + 9 - | \sqrt{3} - 2 | + 5 \sqrt{3} \\ b = 12 - 6 \sqrt{3} - 2 + \sqrt{3} + 5 \sqrt{3} \\ b = 10 \\ \\ \\ b) \: \: \: a = 7 \sqrt{2} = \sqrt{98} \\ \: \: \: \: \: \: b = 10 = \sqrt{100} \\ = > a < b[/tex]
