Answer:
x = 25.8
Explanation:
The product of the measures of one secant's external part and the entire secant is equal to the product of the measures of the other secant's external part and the entire secant, that is
5(5 + x) = 7(7 + 15)
25 + 5x = 7 × 22 = 154 ( subtract 25 from both sides )
5x = 129 ( divide both sides by 5 )
x = 25.8