Wait how would you even do this?
Answer:
A scatter plot (aka scatter chart, scatter graph) uses dots to represent values for two different numeric variables. The position of each dot on the horizontal and vertical axis indicates values for an individual data point
Reflecting a function across the x-axis means to change the sign of the function itself: you're mapping 
So, if you have a x/y values table, you simply have to change sign to all the values in the y column.