It is known that the image of inverse scale function y = K / X passes through (1 / 2,8), and the line y = - x + B should pass through the image of inverse scale function (4, m) to find their inverse scale function and the function expression of the line

It is known that the image of inverse scale function y = K / X passes through (1 / 2,8), and the line y = - x + B should pass through the image of inverse scale function (4, m) to find their inverse scale function and the function expression of the line

Because the image of y = K / X passes through (1 / 2,8), then: 8 = 2K, k = 4, that is: y = 4 / X
Because the line y = - x + B should pass through the image of inverse scale function (4, m), then point (4, m) is on the line and inverse scale function: M = 4 / 4 = 1, substituting y = - x + B to get: 1 = - 4 + B, B = - 5. That is y = - X-5