Question

what are the coordinates of the point (5,3) reflected across the X-Axis

Answer 1

we you reflect a point across x-axis you do this

$(x,y)\longrightarrow(x,-y)$

so, the point (5,3) is

$(5,3)\longrightarrow(5,-3)$

to reflect across the x-axis you change the sign of the y coordinate

example

$(2,-1)\longrightarrow(2,1)$