What is $- \sqrt{20} + 3 \sqrt{45}$ $-sqrt(20) + 3 sqrt(45)$ ?

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Answer 1 · 2017-01-22T04:47:42

$7 \sqrt{5}$ $7sqrt(5)$

Factor the numbers under each square root and look for "perfect square" factors
$- \sqrt{(4) (5)} + 3 \sqrt{(9) (5)}$ $-sqrt(color(red)((4)(5))) + 3sqrt(color(red)((9)(5)))$
Separate the terms in the square roots
$- \sqrt{4} \sqrt{5} + 3 \sqrt{9} \sqrt{5}$ $-color(red)(sqrt(4)sqrt(5))+3color(red)(sqrt(9)sqrt(5))$
Simplify the roots ( $\sqrt{4} = 2$ $sqrt(4)=2$ and $\sqrt{9} = 3$ $sqrt(9)=3$ )
$- 2 \sqrt{5} + 3 (3) \sqrt{5}$ $-color(red)(2)sqrt(5)+3color(red)((3))sqrt(5)$
Simplify
$- 2 \sqrt{5} + 9 \sqrt{5}$ $-2sqrt(5)+color(red)(9)sqrt(5)$
Combine terms
$7 \sqrt{5}$ $7sqrt(5)$

What is -sqrt(20) + 3 sqrt(45)−√20+3√45-sqrt(20) + 3 sqrt(45)?