All categories

3 years ago

Anyone know how to solve this ?? I need help

Mathematics

1 answer:

IrinaK [193]3 years ago

7 0

Answer:

x = - 7, x = - 4

Step-by-step explanation:

To factor the quadratic

Consider the factors of the constant term ( + 28) which sum to give the coefficient of the x- term ( + 11)

The factors are + 7 and + 4, since

7 × 4 = 28 and 7 + 4 = 11, hence

(x + 7)(x + 4) = 0

Equate each factor to zero and solve for x

x + 7 = 0 ⇒ x = - 7

x + 4 = 0 ⇒ x = - 4

You might be interested in

How many seconds are there in a month of 30 days express it in scientific notation

Evgesh-ka [11]

Answer: 2.592 x 10^6 seconds

Explanation:

There are 3600s in 1 hr

And 24hrs in 1 day which mean

There are 3600 x 24 = 86400s in 1 day

And one month = 30 days

86400 x 30 = 2, 592, 000s in 1 month

Write in scientific notation:

2, 592, 000 = 2.592 x 10^6

6 0

2 years ago

The shorter tree is 10 ft. tall, and casts a shadow that is 15 feet long. If the taller tree casts a 18 ft. shadow, how tall is

White raven [17]

Answer: The height of the tree is 27 ft

6 0

2 years ago

Help please it’s algebra

amid [387]

Answer:

I'm not sure, but I think they spend 2$ for each

Step-by-step explanation:

The total items they buyed was 45. The total amount of money they spend was 95. 95 divided by 45 is 2.111111111111111111111 . So if you find 2 as one of your options, that's probably it.

8 0

2 years ago

A farmer collected 12 dozen eggs from chickens. She sold 5/6 of the eggs at the farmers market and have the rest to her friends.

kiruha [24]

The answer is 120. Just do 12·12=144. Then 144·5/6=120

3 0

3 years ago

An article reports that 1 in 500 people carry the defective gene that causes inherited colon cancer. In a sample of 2500 individ

Ne4ueva [31]

Answer:

The approximate distribution of the number who carry this gene is approximately normal with mean $\mu = 5$ and standard deviation $\sigma = 2.23$

Step-by-step explanation:

For each person, there are only two possible outcomes. Either they carry the defective gene that causes inherited colon cancer, or they do not. The probability of a person carrying this gene is independent from other people. So the binomial probability distribution is used to solve this question.

A sample of 2500 individuals is quite large, so we use the binomial approximation to the normal to solve this question.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

Can be approximated to a normal distribution, using the expected value and the standard deviation.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

$\sqrt{V(X)} = \sqrt{np(1-p)}$

Normal probability distribution

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

When we are approximating a binomial distribution to a normal one, we have that $\mu = E(X)$ , $\sigma = \sqrt{V(X)}$ .

An article reports that 1 in 500 people carry the defective gene that causes inherited colon cancer.

This means that $p = \frac{1}{500} = 0.002$

In a sample of 2500 individuals, what is the approximate distribution of the number who carry this gene?

$n = 2500$

$\mu = E(X) = np = 2500*0.002 = 5$

$\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{2500*0.002*0.998} = 2.23$

So the approximate distribution of the number who carry this gene is approximately normal with mean $\mu = 5$ and standard deviation $\sigma = 2.23$

4 0

3 years ago