was able to solve it till here can someone please explain

I'm not sure that the x stuff in the top row has to do with anything unless it's a separate problem. In any event, it does not equate to 1 x 1 x 1:

(x^(a) / x^(b))^(a+b) = (x^(a-b))^(a+b) = x^($a-b$$a+b$) = x^(a\^2 - b\^2)

Repeat for the others then see what you can get from there.

For the other problem I would convert all of the roots into fractional powers and distribute over the terms, for example:

√(3 x 5^(-3)) = (3 x 5^(-3))^(1/2) = 3^(1/2) x 5^(-3/2)

Do that for all the others, then add/subtract exponents of like bases as appropriate and see where that gets you.

Also, 5^(4) isn't 20, looks like you mistook it for 5 x 4.