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3 years ago

What are the solutions to the equation? 3x^2+6x=45 Enter your answers in the boxes.

Mathematics

2 answers:

maksim [4K]3 years ago

8 0

Answer:

Step-by-step explanation:

3x² +6x = 45

divid by : 3 :

x² +2x = 15

(x² +2x +1 )-16 = 0

( x + 1 )² - 4² = 0

note : a² - b² = (a - b ) ( a + b) ...idetity

( x +1 -4)( x + 1 +4) = 0

(x -3 ) ( x+5) =0

x-3 = 0 or x +5 = 0

x = 3 or x = - 5

my answer in the boxes : x = 3 and x = -5

Gnoma [55]3 years ago

5 0

x= 3,-5

hope this helps

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4. In a sample of 1000 people, 130 can wiggle their ears. Two unrelated people are

Elina [12.6K]

Using the hypergeometric distribution, it is found that there is a 0.7568 = 75.68% probability that neither can wiggle his or her ears.

The people are chosen from the sample without replacement, which is why the <u>hypergeometric distribution</u> is used to solve this question.

Hypergeometric distribution:

$P(X = x) = h(x,N,n,k) = \frac{C_{k,x}C_{N-k,n-x}}{C_{N,n}}$

$C_{n,x} = \frac{n!}{x!(n-x)!}$

The parameters are:

x is the number of successes.
N is the size of the population.
n is the size of the sample.
k is the total number of desired outcomes.

In this problem:

1000 people means that $N = 1000$
130 can wiggle their ears, thus $k = 130$
Two are selected, thus $n = 2$ .

The probability that neither can wiggle his or her ears is P(X = 0), thus:

$P(X = x) = h(x,N,n,k) = \frac{C_{k,x}C_{N-k,n-x}}{C_{N,n}}$

$P(X = x) = h(0,1000,2,130) = \frac{C_{130,0}C_{870,2}}{C_{1000,2}} = 0.7568$

0.7568 = 75.68% probability that neither can wiggle his or her ears.

A similar problem is given at brainly.com/question/24826394

5 0

2 years ago

A population of mice is increasing exponentially. On Monday there were 120 most. One month later there were 132 most. Ready func

djyliett [7]

Answer:

$y=120 * 1.1^x$ --- function

The monthly rate is 10%

Step-by-step explanation:

Given

Let

$x \to months$

$y \to mice$

So, we have:

$(x_1,y_1) = (0,120)$ --- Monday

$(x_2,y_2) = (1,132)$ --- One month later

Required

The function

The function is represented as:

$y=ab^x$

In $(x_1,y_1) = (0,120)$ , we have:

$120 = a * b^0$

$120 = a * 1$

$120 = a$

$a=120$

In $(x_2,y_2) = (1,132)$ , we have:

$132 = a * b^1$

$132 = a * b$

Substitute: $a=120$

$132 = 120 * b$

Solve for b

$b = \frac{132}{120}$

$b = 1.1$

So, the function is:

$y=ab^x$

$y=120 * 1.1^x$

To calculate the monthly rate (r), we have:

$y =a(1 + r)^x$

Compare to: $y =ab^x$

$1 + r = b$

Make r the subject

$r = b-1$

Substitute $b = 1.1$

$r = 1.1-1$

$r = 0.1$

Express as percentage

$r = 0.1*100\%$

$r = 10\%$

5 0

3 years ago

A tuple is immutable. What does that mean?

Fantom [35]

Answer:

A tuple cannot be changed once it is created.

Step-by-step explanation:

4 0

3 years ago