Pls show me step by step how to solve this

Question

One endpoint of a diameter of a circle centred on the origin is (3,-4). Find the coordinates of the other endpoint of this diameter. 

Answer 1

Since it is centered on the origin, any diameter would pass thru the origin. The slope of that line is the same for every point along it, so the change of x and y from one end to the center equals the change from the other end to the center. Thus, the two endpoints are (3, -4) and (-3, 4)

Answer 2

Draw and label a diagram!!

(-3, 4)