To determine the inverse of a function, we first write the parent function in terms of y. So, in this part the x would be isolated to one side of the equation. Then, with the new form of the parent function, we switch the x into y and y to x. The new function would be the inverse function. For the given function, we do as follows:
y=-4/x + 1
y - 1 = -4/x
x ( y - 1 ) = -4
x = -4 / (y -1)
Replacing x into y and y into x,
y = -4 / (x -1)
Therefore, the inverse is y=-a/x-b where a = 4 and b = 1.