Question

Root under 10 × root under 15

Answer 1

$\sqrt{10} \times \sqrt{15} \\ \\ = \sqrt{10 \times 15} \\ \\ = \sqrt{2 \times 5 \times 3 \times 5} \\ \\ = \sqrt{2 \times 3 \times 5 \times 5} \\ \\ = \sqrt{2 \times 3 \times {5}^{2} } \\ \\ = 5 \sqrt{2 \times 3} \\ \\ = 5 \sqrt{6}$