....................48.5 I think
Answer: 
Step-by-step explanation:
A line that cuts a circle at two points is called "secant".
There is a theorem known as "Intersecting Secant Theorem". This is the theorem you need to use to find the value of "d".
According the Intersecting Secant Theorem:

Having this expression, the next step is to solve for "d":
Use Distributive property:

Subtract 256 from both sides:


Divide both sides by 16:

The value of "d" rounded to the nearest tenth is:

The probability is 1/5 (or if you want it in decimals then it is 0.2) (if you want it in percent then it is 20%)
Hope that helped!!!
So first you distribute the negative to the 6x and 13 which will flip the sign of both of them to -6x and -13 so take away the parentheses and the equation is now 7x-6x-13. You combine the x’s and you get 1x-13 or x-13
The answer is 73 because 8 is more than 5 so it rounds up to be 73