In order to reflect a function over the x-axis, you need to multiply the whole function by negative 1, that is -1.
Therefore, we would have the following;
[tex]\begin{gathered} f(x)=2x-9 \\ f(x)^{\prime}=(2x-9)(-1) \\ f(x)^{\prime}=-2x+9 \end{gathered}[/tex]Reflecting the given function over the x-axis results in the equation shown above.
