Question

y=cube root of 5 + 1 by cube root of 5, show that 5y cube - 15y = 26

Answer 1

$y = (\sqrt[3]{5} + 1) \div \\ \sqrt[3]{5} \\ cubng \: on \: both \: so \\ sides \: we \: have \\ {y}^{3} = 5 + 1 + 3 \sqrt[3]{5} ( \sqrt[3]{5} + 1) \div 5 \\ {y}^{3} = 6 + 3 \sqrt[3]{5} ( \sqrt[3]{5} + 1) \div 5 \\ 5(6 + 3 \sqrt[3]{5} ( \sqrt[3]{5} + 1)) - 15( \sqrt[3]{y} + 1) =$

$30 + 15 \sqrt[3]{5} ( \sqrt[3]{5} + 1) \\ \sqrt{?}$

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