Question 679175
{{{sqrt(20)+sqrt(45)-sqrt(5) = sqrt(4*5)+sqrt(9*5)-sqrt(5)}}}
...
{{{2sqrt(5)+3sqrt(5)-1sqrt(5) = highlight_green(4sqrt(5))}}}

.....................
Delighted to help; feel free to email if you have further questions.
HomeworkHelpers@readingboosters.com
-Reading Boosters
Website: www.MyHomeworkAnswers.com 
Wanting for others what we want for ourselves.