I think I did these correctly but before I do anymore of the same problems I was wondering if you guys could check them for me

Simplify with no radicals or negative exponents:

1. (x(squareroot 16xt^2))^2

I'm not certain what sign to use on the keyboard for squareroot symbo

Well this is what I did.

(x^2)(16xt^2)

16x^3t^2

2. (3ab)^-1(a^2b^-1)^2

(a^2)(b^-2) / (3ab)

a^2 / 3ab^3

a / 3b^3

Any help or advice would be great