Given the function y = (A-X) / (x-a-1), the center of symmetry of the image is (3, - 1), then the real number a is equal to

Given the function y = (A-X) / (x-a-1), the center of symmetry of the image is (3, - 1), then the real number a is equal to

It is known that y = (A-X) / (x-a-1) = [- (x-a-1) - 1] / (x-a-1) = - 1-1 / (x-a-1),
The results show that y + 1 = - 1 / (x-a-1),
The symmetry center of the function image is (a + 1, - 1),
A + 1 = 3,
The solution is a = 2