Question 215611
        {{{(15y^3)/( (25t^3y^4)-(20uy^5))}}}

Divide numerator and denominator by y*3:

        {{{(15)/( (25t^3y)-(20uy^2))}}}

Divide numerator and denominator by 5:

        {{{3/( 5t^3y-(4uy^2))}}}

That's it!