30 pts BRIANLIEST Help

c

Step-by-step explanation:

Given a tangent- secant from an external point to the circle, then

The product of the external part and the entire secant is equal to the square of the tangent, that is

8(8 - 4 + 2x) = 12²

8(4 + 2x) = 144 ( divide both sides by 8 )

4 + 2x = 18 ( subtract 4 from both sides )

2x = 14 ( divide both sides by 2 )

x = 7

Thus

QS = 8 - 4 + 2x = 4 + 2x = 4 + 2(7) = 4 + 14 = 18 → c

c

step-by-step explanation: