Answer:
x = 3
Explanation:
Two secants from an external point to the circle.
The product of the external part and the whole of one secant is equal to the product of the external part and the whole of the other secant, that is
7(5x + 2 + 7) = 8(3x + 4 + 8), that is
7(5x + 9) = 8(3x + 12) ← distribute parenthesis on both sides
35x + 63 = 24x + 96 ( subtract 24x from both sides )
11x + 63 = 96 ( subtract 63 from both sides )
11x = 33 ( divide both sides by 11 )
x = 3