Answer:
x = 1
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
8(8 + 10x) = 9(9 + 7x) ← distribute parenthesis
64 + 80x = 81 + 63x ( subtract 63x from both sides )
64 + 17x = 81 ( subtract 64 from both sides )
17x = 17 ( divide both sides by 17 )
x = 1