Explanation:
what is the problem here you don't understand ?
you understand the words "equality" and "inequality" ?
this is all about the question, if something is equal to something else or not - meaning of they are the same or at least the same size.
an expression without an equal ("=") or unequal sign ("<", ">", ">=", "<=", "<>" - if you don't understand these symbols, please ask, they are simply basic keyboard symbols for the scientific symbols) is not any form of that - no equality, and no inequality.
so,
1. is NOT
2. is NOT because it has an equality symbol
3. is a quadratic inequality (when doing the multiplication of both bracket terms, there will be an x×x=x² part) - it has a ">" (greater) symbol
4. is a quadratic inequality (there is a x² term as highest power of x included) - it has a "<=" (smaller or equal) symbol
5. is a quadratic inequality (there is a x² term as highest power of x included) - it has a ">" (greater) symbol