2x^2-7=4
subtract 4 from both sdies
2x^2-11=0
therefor
2x^2=11
divide by 2
x^2=5.5
square root both sdies
x=-2.345 or 2.345
Answer:
<em>x </em>= -2
<em>y </em>= 0
Step-by-step explanation:
Pretty hard process, but let me explain:
First, solve for y.
Substitute -x - 2 for y in x - y = -2:
Then, simplify both sides of the equation.
x - y = -2
x - (-x - 2) = -2
After, add -2 to both sides of the equation.
2x + 2 = -2
2x + 2 + -2 = -2 + -2
Next, divided both sides by 2.
2x/2 = -4/2
After that, substitute -2 for x in y = -x - 2:
You must simplify both sides of the equation.
y = -x - 2
y = -(-2) - 2
y = 0
Sorry if this is long and confusing, but I hope this helps!!
Answer:
119°
Step-by-step explanation:
It’s 119. You don’t need to solve for h.
Using the binomial distribution, it is found that there is a:
a) 0.9298 = 92.98% probability that at least 8 of them passed.
b) 0.0001 = 0.01% probability that fewer than 5 passed.
For each student, there are only two possible outcomes, either they passed, or they did not pass. The probability of a student passing is independent of any other student, hence, the binomial distribution is used to solve this question.
<h3>What is the binomial probability distribution formula?</h3>
The formula is:
![P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}](https://tex.z-dn.net/?f=P%28X%20%3D%20x%29%20%3D%20C_%7Bn%2Cx%7D.p%5E%7Bx%7D.%281-p%29%5E%7Bn-x%7D)
![C_{n,x} = \frac{n!}{x!(n-x)!}](https://tex.z-dn.net/?f=C_%7Bn%2Cx%7D%20%3D%20%5Cfrac%7Bn%21%7D%7Bx%21%28n-x%29%21%7D)
The parameters are:
- x is the number of successes.
- n is the number of trials.
- p is the probability of a success on a single trial.
In this problem:
- 90% of the students passed, hence
.
- The professor randomly selected 10 exams, hence
.
Item a:
The probability is:
![P(X \geq 8) = P(X = 8) + P(X = 9) + P(X = 10)](https://tex.z-dn.net/?f=P%28X%20%5Cgeq%208%29%20%3D%20P%28X%20%3D%208%29%20%2B%20P%28X%20%3D%209%29%20%2B%20P%28X%20%3D%2010%29)
In which:
![P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}](https://tex.z-dn.net/?f=P%28X%20%3D%20x%29%20%3D%20C_%7Bn%2Cx%7D.p%5E%7Bx%7D.%281-p%29%5E%7Bn-x%7D)
![P(X = 8) = C_{10,8}.(0.9)^{8}.(0.1)^{2} = 0.1937](https://tex.z-dn.net/?f=P%28X%20%3D%208%29%20%3D%20C_%7B10%2C8%7D.%280.9%29%5E%7B8%7D.%280.1%29%5E%7B2%7D%20%3D%200.1937)
![P(X = 9) = C_{10,9}.(0.9)^{9}.(0.1)^{1} = 0.3874](https://tex.z-dn.net/?f=P%28X%20%3D%209%29%20%3D%20C_%7B10%2C9%7D.%280.9%29%5E%7B9%7D.%280.1%29%5E%7B1%7D%20%3D%200.3874)
![P(X = 10) = C_{10,10}.(0.9)^{10}.(0.1)^{0} = 0.3487](https://tex.z-dn.net/?f=P%28X%20%3D%2010%29%20%3D%20C_%7B10%2C10%7D.%280.9%29%5E%7B10%7D.%280.1%29%5E%7B0%7D%20%3D%200.3487)
Then:
![P(X \geq 8) = P(X = 8) + P(X = 9) + P(X = 10) = 0.1937 + 0.3874 + 0.3487 = 0.9298](https://tex.z-dn.net/?f=P%28X%20%5Cgeq%208%29%20%3D%20P%28X%20%3D%208%29%20%2B%20P%28X%20%3D%209%29%20%2B%20P%28X%20%3D%2010%29%20%3D%200.1937%20%2B%200.3874%20%2B%200.3487%20%3D%200.9298)
0.9298 = 92.98% probability that at least 8 of them passed.
Item b:
The probability is:
![P(X < 5) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4)](https://tex.z-dn.net/?f=P%28X%20%3C%205%29%20%3D%20P%28X%20%3D%200%29%20%2B%20P%28X%20%3D%201%29%20%2B%20P%28X%20%3D%202%29%20%2B%20P%28X%20%3D%203%29%20%2B%20P%28X%20%3D%204%29)
Using the binomial formula, as in item a, to find each probability, then adding them, it is found that:
![P(X < 5) = 0.0001](https://tex.z-dn.net/?f=P%28X%20%3C%205%29%20%3D%200.0001)
Hence:
0.0001 = 0.01% probability that fewer than 5 passed.
You can learn more about the the binomial distribution at brainly.com/question/24863377
If you multiply 20 and 10 you get 200 after that you subtract 100 to get...One hundred