We can use this rule for dividing radicals to rewrite this expression:
sqrt(a)/sqrt(b) = sqrt(a/b)
sqrt(3x^2y^3)/(4sqrt(5xy^3)) => 1/4sqrt((3x^2y^3)/(5xy^3)) => 1/4sqrt((3x^2color(red)(cancel(color(black)(y^3))))/(5xcolor(red)(cancel(color(black)(y^3))))) =>
1/4sqrt((3x^2)/(5x))
Next, we can use these rules of exponents to simplify the x term:
a^color(red)(1) = a or a = a^color(blue)(1) and x^color(red)(a)/x^color(blue)(b) = x^(color(red)(a)-color(blue)(b))
1/4sqrt((3x^2)/(5x)) => 1/4sqrt((3x^color(red)(2))/(5x^color(blue)(1))) => 1/4sqrt((3x^(color(red)(2)-color(blue)(1)))/5) => 1/4sqrt((3x^color(red)(1))/5) =>
1/4sqrt((3x)/5)