Question

root80+3root245-root125

Answer 1

$\sqrt{80} + 3 \sqrt{245} - \sqrt{125} \\ \\ on \: splitting \: we \: get \\ \\ \sqrt{2 \times 2 \times 2 \times 2 \times 5 } + 3 \sqrt{5 \times 7 \times 7} - \sqrt{5 \times 5 \times 5} \\ \\ = 2 \times 2 \sqrt{5} + 3 \times 7\sqrt{5} - 5 \sqrt{5} \\ \\ = 4 \sqrt{5} + 21 \sqrt{5} - 5 \sqrt{5} \\ \\ = 25 \sqrt{5} - 5 \sqrt{5} \\ \\ = 20 \sqrt{5}$