Answer:
x = 5
Explanation:
given 2 secants to a circle from an external point , then
the product of the measures of one secant's external part and that entire secant is equal to the product of the measures of the other secant's external part and that entire secant , that is
(x - 1)(x - 1 - 3 + x) = 3(3 + 5)
(x - 1)(2x - 4) = 3(8) ← expand factors on left side using FOIL
2x² - 6x + 4 = 24 ( subtract 24 from both sides )
2x² - 6x - 20 = 0 ( divide through by 2 )
x² - 3x - 10 = 0 ← in standard form
(x - 5)(x + 2) = 0 ← in factored form
equate each factor to zero and solve for x
x - 5 = 0 ⇒ x = 5
x + 2 = 0 ⇒ x = - 2
however, x > 0 , then x = 5