9514 1404 393
Answer:
x = 7
Explanation:
The product of secant lengths to the two intersection points is the same for both secants.
(AD)(AE) = (AB)(AC)
8(8+10) = (x-1)(x-1 +x+11)
144 = 2x^2 +8x -10
x^2 +4x -77 = 0
(x +11)(x -7) = 0
Solutions to this quadratic are x = -11, x = 7. (These values make the factors zero.) Only the positive solution is useful here
x = 7