Question 156145
Are you trying to find the domain of {{{f(x)=x^2+x}}} ??


If you are, then notice how there is no division by a variable or a square root of a variable. This means that we don't have to worry about division by zero or taking the square root of a negative number. So this means that we can plug in <b>any</b> number into {{{f(x)=x^2+x}}} and it will result in a real number.



So the domain is all real numbers. 



The domain in set-builder notation is *[Tex \LARGE \left\{x\|x\in \mathbb{R}\right\}]


Also the domain in interval notation is  <font size="6">(</font>*[Tex -\infty,\infty\LARGE ]<font size="6">)</font>