The rule for secants is that the product of segment lengths (on the same line) from the point of intersection to the points on the circle is a constant for any given point of intersection. Here, that means ...
... 3×(3+5) = 4×(4+x)
... 6 = 4+x . . . . divide by 4
... 2 = x . . . . . . subtract 4
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<em>Comment on this secant relationship</em>
Expressed in this way, the relationship is true whether the point of intersection is inside the circle or outside.