It is 23/4 in its simplest form
0.575 is a fraction. It is a fraction in decimal form rather than in the form of a ratio. However, that does not stop it being a fraction. Its rational equivalent is 575/1000 which can be simplified, if required.
575 is an integer, not a fraction. There is not really a sensible way of writing it as a fraction or mixed number.
5.75 isa fraction. It is a fraction in decimal form rather than in the form of a ratio. However, that does not stop it being a fraction. Its equivalent, in rational form, is 575/100. You can simplify this rational fraction if you so wish.
5.8 as an improper fraction is 58/10.
If the improper fraction is greter than 0 it is the value of the improper fraction and if the improper fraction is less than 0, it is the negative of the value of the fraction.
4.27 as an improper fraction is 427/100
4/9 is a proper fraction and there is not an improper version.4/9 is a proper fraction and there is not an improper version.4/9 is a proper fraction and there is not an improper version.4/9 is a proper fraction and there is not an improper version.
Improper fraction is greater than a proper fraction.
An improper fraction is a fraction. It can't become a proper fraction.
It remains an improper fraction.
There is no equivalent improper fraction.
There is no equivalent improper fraction.