show that x(-4,-3) and y(4,3) are endpoints of a diameter of the circle x^2 + y^2 = 25
Part 1 :
the centre of x^2 + y^2 = 25 is (0,0)
the midpoint of the line from x to y is (0,0) , so the line runs through the centre as a diameter should
Part 2:
both of the given points satisfy the equation, so they must lie on the circle.
So a line which falls on the circle and runs through the centre must be a diameter