Please help I’ll give Brainly please please

Answer:
20, 8, 3√6 (If you need anymore just comment)
Step-by-step explanation:
Let's start with √400
We start by factoring it
400: 4*100
These are two perfect squares. We find the square root of both of them and get 2*10 which is 20. So square root 400 is 20
∛512
Same thing 512: 8*64
Notice that 64=8*8 so 512 = 8^3 therefore the answer is 8
√54
54=9*6
Notice only 9 is a perfect square
So this gives us 3√6
And that's it!