Answer:
AB = 7
Explanation:
When 2 secants intersect a circle from an external point, then
CB × CA = CD × CE, that is
5(5 - 4 + x) = 6(6 + 4) ← simplify left side
5(1 + x) = 6 × 10 ← distribute left side
5 + 5x = 60 ( subtract 5 from both sides )
5x = 55 ( divide both sides by 5 )
x = 11
Hence
AB = - 4 + x = - 4 + 11 = 7