Answer:
Explanation:
A reflection over the x-axis changes all the y-values. The reflection is modeled as -f(x)
For example:
 would look like --
 would look like --
 .
 .
If the negative sign is outside of the bracket ( what it's called sorry), then it is a reflection over the x-axis
However if the negative sign was inside the bracket: 
 then this would be a reflection over the y axis.
 then this would be a reflection over the y axis. 
Hope this helps!