Question

can someone explain to me how to simplify expression and write as positive exponent
(2x/y)^-3

Answer 1

2xy^3

Recall that 1/x=x^(-1)

Also vice versa.

1/x^(-1)=x^(1)=x

Answer 2

Alternatively, 1/x^(-3)=x^3

You can apply this to your problem to give 2xy^3