What shape is this

4, Find a number x such that x = 1 mod 4, x 2 mod 7, and x 5 mod 9.

olchik [2.2K]

4, 7 and 9 are mutually coprime, so you can use the Chinese remainder theorem.

Start with

$x=7\cdot9+4\cdot2\cdot9+4\cdot7\cdot5$

Taken mod 4, the last two terms vanish and we're left with

$x\equiv63\equiv64-1\equiv-1\equiv3\pmod4$

We have $3^2\equiv9\equiv1\pmod4$ , so we can multiply the first term by 3 to guarantee that we end up with 1 mod 4.

$x=7\cdot9\cdot3+4\cdot2\cdot9+4\cdot7\cdot5$

Taken mod 7, the first and last terms vanish and we're left with

$x\equiv72\equiv2\pmod7$

which is what we want, so no adjustments needed here.

$x=7\cdot9\cdot3+4\cdot2\cdot9+4\cdot7\cdot5$

Taken mod 9, the first two terms vanish and we're left with

$x\equiv140\equiv5\pmod9$

so we don't need to make any adjustments here, and we end up with $x=401$ .

By the Chinese remainder theorem, we find that any $x$ such that

$x\equiv401\pmod{4\cdot7\cdot9}\implies x\equiv149\pmod{252}$

is a solution to this system, i.e. $x=149+252n$ for any integer $n$ , the smallest and positive of which is 149.

3 0

3 years ago

I need some DETAILED examples of Dividing Integers! Urgent, pls help ASAP!

vfiekz [6]

Here are some examples:

Integers are positive and negative numbers, but dividing integers are dividing positive and negative numbers:

Remember these rules:

Negative divided by a negative equals a positive.
Negative divided by a positive equals a negative.
Positive divided by a positive equals a positive .

Examples:

$-4 \div 2 = -2$
$-4 \div -4 = 1$
$4 \div 2 = 2$

Hope this helps!

8 0

3 years ago

If f(x)=3x+2 what is the equation for f^-1(x)

Elden [556K]

Answer:

f^-1(x) = (x -2)/3

Step-by-step explanation:

To find the inverse function, swap x and y, then solve for y.

y = 3x +2 . . . . given function

x = 3y +2 . . . . inverse relation

x -2 = 3y . . . . subtract 2

(x -2)/3 = y . . . divide by 3

f^-1(x) = (x -2)/3 . . . . in functional form

4 0

3 years ago

The mean annual cost of an automotive insurance policy is normally distributed with a mean of $1140 and standard deviation of $3

DerKrebs [107]

Using the normal distribution, it is found that the probabilities are given as follows:

a) 0.8871 = 88.71%.

b) 0.0778 = 7.78%.

c) 0.8485 = 84.85%.

<h3>Normal Probability Distribution</h3>

The z-score of a measure X of a normally distributed variable with mean $\mu$ and standard deviation $\sigma$ is given by:

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

The z-score measures how many standard deviations the measure is above or below the mean.

Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.

By the Central Limit Theorem, the sampling distribution of sample means of size n has standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

The parameters in this problem are given as follows:

$\mu = 1140, \sigma = 310, n = 16, s = \frac{310}{\sqrt{16}} = 77.5$

Item a:

The probability is the <u>p-value of Z when X = 1250 subtracted by the p-value of Z when X = 1000</u>, hence:

X = 1250:

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

By the Central Limit Theorem

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

$Z = \frac{1250 - 1140}{77.5}$

Z = 1.42

Z = 1.42 has a p-value of 0.9222.

X = 1000:

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

$Z = \frac{1000 - 1140}{77.5}$

Z = -1.81

Z = -1.81 has a p-value of 0.0351.

0.9222 - 0.0351 = 0.8871 = 88.71% probability.

Item b:

The probability is <u>one subtracted by the p-value of Z when X = 1250</u>, hence:

1 - 0.9222 = 0.0778 = 7.78%.

Item c:

The probability is the <u>p-value of Z when X = 1220</u>, hence:

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

$Z = \frac{1220 - 1140}{77.5}$

Z = 1.03

Z = 1.03 has a p-value of 0.8485.

0.8485 = 84.85% probability.

More can be learned about the normal distribution at brainly.com/question/4079902

#SPJ1

3 0

2 years ago

Need help asap with this Algebra question!!

Charra [1.4K]

The answer is A.35 sorry if I’m wrong

3 0

3 years ago

What shape is this ​

What shape is this