Answer:
x = 5
Explanation:
There's a Secant Theorem that someone else figured out (waaaay back in history) we just need to memorize it. So a secant is a line that touches the circle in two places. Your picture has two secants that both go thru the same point that's outside the circle. The secants each have a bit that's inside the circle and a bit that's outside the circle. And we could add together the inside and outside bits and get a total for the whole thing.
The secant theorem says that the outside piece × the whole thing on one secant = the outside piece × the whole thing on the other secant.
For the secant on top the "outside" bit is 9 and the whole thing is (2x+1+9). We'll times these together.
For the bottom secant the outside piece is 10 and the whole thing is (x+3+10). We'll multiply these together.
9(2x+1+9)=10(x+3+10)
simplify.
9(2x+10) = 10(x+13)
distribute.
18x + 90 = 101x + 130
combine like terms.
8x + 90 = 130
subtract 90
8x = 40
divide by 8
x = 5
see image.