Question

find the co-ordinates of A

Answer 1

CoordinatesofA are(5,1

Answer 2

As A is on x axis then ordinate will be 0 and applying distance formula you can find the answer as the distance is given and the coordinates are given therefore.
$5 = \sqrt{(x - 5) ^{2} + (0 - ( - 4))} \\ 5 = \sqrt{x^{2} + 25 - 10x + 16 } \\ when \: squared \\ 25 = x^{2} + 25 - 10x+16 \\ 0 = {x}^{2} - 10x + 16 \\ {x}^{2} - 2x - 8x + 16 = 0 \\ x(x - 2) - 8(x - 2) = 0 \\ (x - 2)(x - 8) = 0 \\ x = 2 \: or \: x = 8$
See the full formula.

therefore the coordinates of A can be (2,0) or (8,0)
Hope this answer will be helpful to you.