All categories

3 years ago

X2 + 16x – 2 = 11

Mathematics

1 answer:

lord [1]3 years ago

6 0

Answer:

(x+8)^2=77 and x=negative 8±√77

Step-by-step explanation:

After watching a video, I got it right on Khan

You might be interested in

There’s a positive correlation between the reading level of a child and how far they can jump. Which variable is most likely the

JulsSmile [24]

A lurking variable within statistics is one that is correlated to both the independent variable (a variable that is varied) and the dependent variable (a variable that is measured). A positive correlation between jumping distance and reading ability within a child is likely to be due to the child's age (answer c).

8 0

3 years ago

Read 2 more answers

What is the decimal for 2/3

lakkis [162]

0.6 repeating (AKA 0.6666666-----)

7 0

3 years ago

If sin(a) = cos(2a), then what is the value of a?

Mariulka [41]

Answer:

-90 , 30

Step-by-step explanation:

sina = cos(2a)

= 1 - 2(sina)^2

2(sina)^2 + sina -- 1 = 0

( sina + 1 )( 2sina - 1 ) = 0

sina = -1 or sina = 1/2

=> a = -90 degrees or => a = 30 degrees

3 0

3 years ago

Suppose that the number of square feet per house are normally distributed with an unknown mean and standard deviation. A random

astraxan [27]

Answer:

1. The margin of error is of 66.96 square feet.

2. The 95% confidence interval estimate for the population mean using the Student's t-distribution is between 1433.04 square feet and 1566.96 square feet

Step-by-step explanation:

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 22 - 1 = 21

95% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 21 degrees of freedom(y-axis) and a confidence level of $1 - \frac{1 - 0.95}{2} = 0.975$ . So we have T = 2.08

The margin of error is:

$M = T\frac{s}{\sqrt{n}} = 2.08*\frac{151}{\sqrt{22}} = 66.96$

In which s is the standard deviation of the sample.

The margin of error is of 66.96 square feet.

The lower end of the interval is the sample mean subtracted by M. So it is 1500 - 66.96 = 1433.04 square feet

The upper end of the interval is the sample mean added to M. So it is 1500 + 314 = 1566.96 square feet

The 95% confidence interval estimate for the population mean using the Student's t-distribution is between 1433.04 square feet and 1566.96 square feet

6 0

3 years ago

A major hurricane is a hurricane with wind speeds of 111 miles per hour or greater. During the 20th century the mean number of t

Bas_tet [7]

Answer:

a) 0.3293 = 32.93% probability that the number of major hurricane to strike U.S mainland in any any give year is exactly one.

b) 0.878 = 87.8% probability that the number of major hurricane to strike U.S mainland in any any give year is at most one.

c) 0.122 = 12.2% probability that the number of major hurricane to strike U.S mainland in any any give year is more than one.

Step-by-step explanation:

We have the mean during an interval, which means that the Poisson distribution is used to solve this question.

In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:

$P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}$

In which

x is the number of sucesses

e = 2.71828 is the Euler number

$\mu$ is the mean in the given interval.

During the 20th century the mean number of the major hurricanes to strike U.S mainland per year was 0.6.

This means that $\mu = 0.6$

Find the probability that the number of major hurricane to strike U.S mainland in any any give year is:

a) Exactly one

This is P(X = 1). So

$P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}$

$P(X = 1) = \frac{e^{-0.6}*0.6^{1}}{(1)!} = 0.3293$

0.3293 = 32.93% probability that the number of major hurricane to strike U.S mainland in any any give year is exactly one.

b) At most one

This is:

$P(X \leq 1) = P(X = 0) + P(X = 1)$

Then

$P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}$

$P(X = 0) = \frac{e^{-0.6}*0.6^{0}}{(0)!} = 0.5488$

$P(X = 1) = \frac{e^{-0.6}*0.6^{1}}{(1)!} = 0.3293$

$P(X \leq 1) = P(X = 0) + P(X = 1) = 0.5488 + 0.3292 = 0.878$

0.878 = 87.8% probability that the number of major hurricane to strike U.S mainland in any any give year is at most one.

c) More than one

This is:

$P(X > 1) = 1 - P(X \leq 1) = 1 - 0.878 = 0.122$

0.122 = 12.2% probability that the number of major hurricane to strike U.S mainland in any any give year is more than one.

6 0

3 years ago