Question

Simplify
$\sqrt{45} + \sqrt{80} - 3 \sqrt{20}$
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Answer 1

√45+√80-3√20=√9×5 +√16×5 -3√4×5

3√5+4√5-6√5=√5

Answer 2

$\sqrt{45} + \sqrt{80} - 3 \sqrt{20}$

$\sqrt{9 \times 5} + \sqrt{16 \times 5} - \sqrt{9 \times 20}$

$3 \sqrt{5} + 4 \sqrt{5} - \sqrt{180}$

$7 \sqrt{5} - \sqrt{36 \times 5}$

$7 \sqrt{5} - 6 \sqrt{5}$

$= \sqrt{5}$