Answer:
a

b

Step-by-step explanation:
From the question we are told that
The number of students in the class is N = 20 (This is the population )
The number of student that will cheat is k = 3
The number of students that he is focused on is n = 4
Generally the probability distribution that defines this question is the Hyper geometrically distributed because four students are focused on without replacing them in the class (i.e in the generally population) and population contains exactly three student that will cheat.
Generally probability mass function is mathematically represented as

Here C stands for combination , hence we will be making use of the combination functionality in our calculators
Generally the that he finds at least one of the students cheating when he focus his attention on four randomly chosen students during the exam is mathematically represented as

Here




Hence


Generally the that he finds at least one of the students cheating when he focus his attention on six randomly chosen students during the exam is mathematically represented as

![P(X \ge 1) =1- [ \frac{^{k}C_x * ^{N-k}C_{n-x}}{^{N}C_n}]](https://tex.z-dn.net/?f=P%28X%20%20%5Cge%201%29%20%3D1-%20%5B%20%20%5Cfrac%7B%5E%7Bk%7DC_x%20%2A%20%5E%7BN-k%7DC_%7Bn-x%7D%7D%7B%5E%7BN%7DC_n%7D%5D%20)
Here n = 6
So
![P(X \ge 1) =1- [ \frac{^{3}C_0 * ^{20 -3}C_{6-0}}{^{20}C_6}]](https://tex.z-dn.net/?f=P%28X%20%20%5Cge%201%29%20%3D1-%20%5B%20%20%5Cfrac%7B%5E%7B3%7DC_0%20%2A%20%5E%7B20%20-3%7DC_%7B6-0%7D%7D%7B%5E%7B20%7DC_6%7D%5D%20)
![P(X \ge 1) =1- [ \frac{^{3}C_0 * ^{17}C_{6}}{^{20}C_6}]](https://tex.z-dn.net/?f=P%28X%20%20%5Cge%201%29%20%3D1-%20%5B%20%20%5Cfrac%7B%5E%7B3%7DC_0%20%2A%20%5E%7B17%7DC_%7B6%7D%7D%7B%5E%7B20%7DC_6%7D%5D%20)
![P(X \ge 1) =1- [ \frac{1 * 12376}{38760}]](https://tex.z-dn.net/?f=P%28X%20%20%5Cge%201%29%20%3D1-%20%5B%20%20%5Cfrac%7B1%20%20%2A%20%2012376%7D%7B38760%7D%5D%20)


Answer:
X = 5
Step-by-step explanation:
3x + 12 + 9x = 72
okay hopefully i can explain so when your doing this combine like terms so
3x + 9x = 12x
12x + 12 = 72
then you would subtract both sides by 12
+12 = subtract x+12=2
- 12 = add x-12=2
there just flipped so in this case i would subtract 12
12x + ( 12-12) = ( 72-12 )
so 12-12 = 0 and 72-12 is equal to 60
12x = 60
the divide on both sides l but leave the x alone so its just 60 divided by 12 wich is 5
so X = 5
hope this helps with ur homework a little btw go back and redo ur other awnsers with this new concept hope it helps
Answer:
x²-10x+34=0. here u go I'm 12
The equation will be 2x + 7 = 3x
subtract 2x from bothsides, you get 7 = x
so x is equal to 7
EDITED
sorry, i didnt read the sum part, so my answer is considered wrong ahaha
2(x+7) equals 3x
distribute, you get 2x+14=3x
then subtract 2x,
the answer for x is 14
I hope this help with your questions let me know if you have more
Have a nice day :)