If x and y are inversely proportional, then which one is true?

x1/y1 = x2/y2 x1/x2 = y1/y2 x1/x2 = y2/y1 x1.x2 = y1.y2

x1/x2 = y2/y1

x∝1/y x=k(1/y) xy=k x1y1=x2y2 x1/x2=y2/y1