x axis is the ones that goes left and right
(x,y)
symetric about the x axis means that the vertical distance from the x axis is the same for 2 points that are symetric about the x axis
y is height
(x,y)
(5,2)
2 is height
distance from x axis
therefor the other point is -2
(5,-2)
the other vertex is at (5,-2)