I can see from the image that all quantities are symbolic. That's not enough information to guarantee a unique solution. Are you sure there's no other known information?
The given tangent line is:
a·x + b·y + c = 0
The coordinates for the given points appear to be subscripted symbols for x and y, but I cannot read the subscripts. I'll use letters:
A(xA, yA)
B(xB, yB)
Here's an example of given coordinates for points A and B, along with given parameters (estimated) for the tangent line:
xA = 1/3 + 2·√2/3
yA = 4·√2/3 - 5/3
xB = 11/17 + 18·√2/17
yB = 4·√2/17 - 7/17
a ≈ 1.39814951
b = -1
c ≈ -7.24185978
With these givens, either of the following is possible.
A circle of radius 4 centered at (3, 1+2√2)
A circle of radius √5 centered at (1, -2)
In this example, how would we determine which circle they're talking about?