You use the rule , y2-y1/x2-x1 , to find the slope so the answer will be = 0-2/4-1 = -2/3
Without that value, we can't solve your problem, unless you are looking for an algebraic equation.
When you reflect a point across the x-axis, the x-coordinate remains the same, but the y-coordinate is transformed into its opposite (its sign is changed). If you forget the rules for reflections when graphing, simply fold your paper along the x-axis (the line of reflection) to see where the new figure will be located.
I believe it is x=55. I could be wrong lol