Question

Simplify:(2 root 5 - 3 root 3)(4 root 5 + root 3)​

Answer 1

$(2 \sqrt{5} - 3 \sqrt{3} )(4 \sqrt{5} + \sqrt{3} ) \\ = 8( { \sqrt{5} })^{2} + 2 \sqrt{5} \sqrt{3} - 12 \sqrt{3} \sqrt{5} - 3( { \sqrt{3} })^{2} \\ = 40 + 2 \sqrt{15} - 12 \sqrt{15} - 9 \\ = 31 - 10 \sqrt{15}$

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