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3 years ago

Add. 8x - 7 + 6x + 8 Help. I might be dumb for not knowing this but please help

Mathematics

2 answers:

Lelu [443]3 years ago

8 0

Answer:

Step-by-step explanation:

nydimaria [60]3 years ago

7 0

Answer:

14 x + 1

Step-by-step explanation:

You aren't dumb, your teacher can't teach!

First we must add the x values together:

8x - 7 + 6x + 8

8 + 6 = 14

14x -7 + 8

Now we add the constants (regular numbers):

14x -7 + 8

-7 + 8

14x +1

There we go!

8x -7 + 6x +8

14x +1

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Which phrases can be represented by the expression StartFraction h Over 30 EndFraction? Check all that apply.

netineya [11]

Answer:

1, 4, 5

Step-by-step explanation:

This is the equation:

$\frac{h}{30} = quotient$

So because 1 and 4 are right because they both describe the quotient being of h and 30. 5 is right because fractions are really just the numerators divided by denominators (h÷30).

6 0

3 years ago

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Distribute 3(7y − 1)

Pepsi [2]

Answer:

it would be 28y minus 3

Step-by-step explanation:

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3 years ago

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5.2.14. For the negative binomial pdf p (k; p, r) = k+r−1 (1 − p)kpr, find the maximum likelihood k estimator for p if r is know

Volgvan

Answer:

$\hat p = \frac{r}{\bar x +r}$

Step-by-step explanation:

A negative binomial random variable "is the number X of repeated trials to produce r successes in a negative binomial experiment. The probability distribution of a negative binomial random variable is called a negative binomial distribution, this distribution is known as the Pascal distribution".

And the probability mass function is given by:

$P(X=x) = (x+r-1 C k)p^r (1-p)^{x}$

Where r represent the number successes after the k failures and p is the probability of a success on any given trial.

Solution to the problem

For this case the likehoof function is given by:

$L(\theta , x_i) = \prod_{i=1}^n f(\theta ,x_i)$

If we replace the mass function we got:

$L(p, x_i) = \prod_{i=1}^n (x_i +r-1 C k) p^r (1-p)^{x_i}$

When we take the derivate of the likehood function we got:

$l(p,x_i) = \sum_{i=1}^n [log (x_i +r-1 C k) + r log(p) + x_i log(1-p)]$

And in order to estimate the likehood estimator for p we need to take the derivate from the last expression and we got:

$\frac{dl(p,x_i)}{dp} = \sum_{i=1}^n \frac{r}{p} -\frac{x_i}{1-p}$

And we can separete the sum and we got:

$\frac{dl(p,x_i)}{dp} = \sum_{i=1}^n \frac{r}{p} -\sum_{i=1}^n \frac{x_i}{1-p}$

Now we need to find the critical point setting equal to zero this derivate and we got:

$\frac{dl(p,x_i)}{dp} = \sum_{i=1}^n \frac{r}{p} -\sum_{i=1}^n \frac{x_i}{1-p}=0$

$\sum_{i=1}^n \frac{r}{p} =\sum_{i=1}^n \frac{x_i}{1-p}$

For the left and right part of the expression we just have this using the properties for a sum and taking in count that p is a fixed value:

$\frac{nr}{p}= \frac{\sum_{i=1}^n x_i}{1-p}$

Now we need to solve the value of $\hat p$ from the last equation like this:

$nr(1-p) = p \sum_{i=1}^n x_i$

$nr -nrp =p \sum_{i=1}^n x_i$

$p \sum_{i=1}^n x_i +nrp = nr$

$p[\sum_{i=1}^n x_i +nr]= nr$

And if we solve for $\hat p$ we got:

$\hat p = \frac{nr}{\sum_{i=1}^n x_i +nr}$

And if we divide numerator and denominator by n we got:

$\hat p = \frac{r}{\bar x +r}$

Since $\bar x = \frac{\sum_{i=1}^n x_i}{n}$

4 0

3 years ago

Kylie is planning to provide online science and Chinese language tutoring sessions. The sciences

Ivahew [28]

Answer:

120 ≤ 20c + 40s

Step-by-step explanation:

(Assuming her name is Kylie, who is giving 40 minute science sessions and 20 minute Chinese sessions.)

The unit for time will be minutes.

Write an equation for time needed for science sessions

40s = t

Write an equation for time needed for Chinese sessions

20c = t

Combine the two equations for the total time.

20c + 40s = total time

She does not want the total time to be more than two hours.

Convert two hours to minutes. There are 60 minutes in an hour.

2h * 60mins = 120 mins

Therefore t ≤ 120. Include this into the equation.

120 ≤ 20c + 40s

8 0

3 years ago

One triangle shown is formed by the tree, its shadow, and a line of sight from the ground to the top of the tree. The other is f

irga5000 [103]

Answer:

21 feet

Step-by-step explanation:

To solve this question, we would be using the proportion

Shadow /Height

From the question:.

Manny's shadow = 414 feet

Manny's Height = 512 feet

Height of the tree = ? = x

Shadow of the tree = 17 feet

Hence:

414/512 = 17/ x

Cross Multiply

414 × x = 512 × 17

x = 512 × 17/414

x = 21.024154589 feet

x ≈ Approximately = 21 feet

The height of the tree = 21 feet

4 0

3 years ago