Answer:
x=4
Explanation:
(whole secant) x (external part) = (tangent)^2
(x+5) *x = 6^2
x^2 +5x = 36
Subtract 36 from each side
x^2 +5x - 36 = 0
Factor
( x-4) (x+9) = 0
Using the zero product property
x-4 = 0 x+9 =0
x = 4 x=-9
Cannot be negative since that is negative length
x=4