Q:

Correct notation for inequality equation

I'm currently taking a Polynomial functions -course and learning about quadratic inequality equations. 
Let's consider this equation:
$-x^{2}+7x<10$
The correct answer to this according to our book is simply 

$x<2$ or $x>5$

But is there any other way to express this in a more mathematical way? I understand why this is expressed the way it is as we haven't learned about set theory yet, but I'd like to know how it is expressed "correctly".

A:

Write it as
$$x \in (-\infty,2)\cup(5,\infty)$$
or $$ x\in R - [2, 5]$$
or $$ x \in \{x: x < 2, x > 5, x\in R\}$$
See set notation for more details:
http://www.mathsisfun.com/sets/set-builder-notation.html

