Ok to start you have to put
2+-1/9 - 4+-1/3
what exactly is the question because without the proper info. nobody is going to be able to figure it out.
Answer:
11.44% probability that exactly 12 members of the sample received a pneumococcal vaccination.
Step-by-step explanation:
For each adult, there are only two possible outcomes. Either they received a pneumococcal vaccination, or they did not. The probability of an adult receiving a pneumococcal vaccination is independent of other adults. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

In which
is the number of different combinations of x objects from a set of n elements, given by the following formula.

And p is the probability of X happening.
70% of U.S. adults aged 65 and over have ever received a pneumococcal vaccination.
This means that 
20 adults
This means that 
Determine the probability that exactly 12 members of the sample received a pneumococcal vaccination.
This is P(X = 12).


11.44% probability that exactly 12 members of the sample received a pneumococcal vaccination.
The common denominator is (x+2)(x-2)
notice that x²-4 is the difference of two square
when you solve it you get (x+2)(x-2). (x+2) can go into (x+2)(x-2).
I think it is your second option 5
Answer:
12
Step-by-step explanation:
By ythagoras Theorem,
x^2 + 9^2 = 15^2
x^2 + 81 = 225
x^2 = 225 - 81
x^2 = 144
x = √144
x = 12