Help with math hw! Simplifying radical expressions.

-4 times radical 100/729

11 times radical 49a^5 over 4a^3

Radical 5 over radical 8x

22 over radical 11

Please help!!! And possibly explain?

1- -4√100/729
-4√10^2/27^2=
-4(10/27)=
-40/27=

2-11√49a^5/4a^3
= 11√7^2 a^5-3/4
= 11√7^2 a^2/2^2
= 11(7a/2)
= 77a/2

3- √5/√8x
= √5/√4*2x
=√5/2√2x

4- 22/√11
= 2√11

10^2 = 100 and 27^2 = 729, so (100/729)^0.5 = 10/27
10/27 * -4 = -40/27

I'm not sure what the second one means; is it 11 * (49a^5/4a^3)^0.5?
If so,
11*(49a^5/4a^3)^0.5
= 11*(49a^2/4)^0.5
= 11*7a/2
=77a/2

(5^0.5)/(8x^0.5) = ((30x)^0.5)/8x

22/11^0.5 = 2*(11^0.5)