Answer:
-7
Step-by-step explanation:
You use the quadratic formula of
to get:
a = 1
b = 7
c = -13
then you plug that into x= (-b ± √b²-4ac)/(2a) :
x= ( -7 ± √7²- 4(1)(-13) )/(2(1))

The sum of these two x values turns out to be:

F(x) = 2x + 1
To find the inverse of a function you just need to switch the x by y or vice-versa:
-> y = 2x + 1
-> x = 2y + 1
After that you isolate the y again:
-> 2y = x - 1
-> y = (x-1)/2
-> f^-1 (x) = (x-1)/2
Answer:
Answer: 12 red balls must be added
Step-by-step explanation:
Starting out with 15 balls, 6 red implies 9 blue. If blue remains 9, then we expect red to be 18 for a probability at 2/3. 18-6 = 12
The answer for your question is C. The reason is I multipled 15 and 6 which gave me 90 and that is closest to the answer C which is 72.73.
Hope this helps:)