Question

$\sqrt{20} +\sqrt{45} - \sqrt{5}$

Answer 1

Answer:

$\sqrt{20} + \sqrt{45} - \sqrt{5} \\ = \sqrt{2 \times 2 \times 5} + \sqrt{3 \times 3 \times 5} - \sqrt{5} \\ = 2 \sqrt{5} + 3 \sqrt{5} - \sqrt{5} \\ = 5 \sqrt{5} - \sqrt{5} \\ = (5 - 1) \sqrt{5} \\ = 4 \sqrt{5}$