Răspuns:
[tex]a = ( \sqrt{ 90} + 5 \sqrt{ 40 } - \sqrt{10} ) \times \sqrt{2} \\ a = (\sqrt{9 \times 10} + 5 \sqrt{4 \times 10} - \sqrt{10} ) \times \sqrt{2} \\ a = ( \sqrt{9} \times \sqrt{10} + 5 \times \sqrt{4} \times \sqrt{10} - \sqrt{10} ) \times \sqrt{2} \\ a = (3 \sqrt{10} + 10 \sqrt{10} - \sqrt{10} ) \times \sqrt{2} \\ a = 12 \sqrt{10} \times \sqrt{2} \\ a = 12 \sqrt{ 20} \\ a = 12 \sqrt{4 \times 5} \\ a = 12 \times 2 \sqrt{5} \\ a = 24 \sqrt{5} [/tex]
[tex]b = \frac{10}{ \sqrt{5} } + \sqrt{125} \\ b = \frac{10 \sqrt{5} }{5} + \sqrt{25 \times 5} \\ b = 2 \sqrt{5} + \sqrt{25} \times \sqrt{5} \\ b = 2 \sqrt{5} + 5 \sqrt{5} \\ b = 7 \sqrt{5} [/tex]
[tex] \frac{a}{b} = \frac{24 \sqrt{5} }{7 \sqrt{5} } \\ \frac{a}{b} = \frac{24}{7} [/tex]
a/b=24/7 €Q
