What is 7√27 + 5√48 in simplified form?

For 7√27 I think you have to see what can come out off the 27

√27

∧

9 3

∧

3 3

A 3 comes out because there is two and the other 3 stays in, so your left with

3·7√3 = 21√3

for 5√48 Two 2s come out and a 3 stays in so, it looks like 4·5√3 = 20√3

and than just add

I hope this looks familiar.