What is the value of x?

How do i round 8.61 to the nearest tenth?

Stells [14]

Its 8.7 because 1 is lower than 6 so you add 7.

7 0

4 years ago

The mean monthly rent of students at Oxnard University is $810 with a standard deviation of $235. (a) John's rent is $1370. What

a_sh-v [17]

Answer:

John's standard z-score is 2.383

Step-by-step explanation:

We are given the following in the question:

Population mean, μ = $810

John's rent = $1370

Population standard deviation, σ = $235

Formula:

$z_{score} = \displaystyle\frac{x-\mu}{\sigma}$

Putting all the values, we have

$z_{score} = \displaystyle\frac{1370 - 810}{235} = 2.383$

John's standard z-score is 2.383

6 0

3 years ago

Let A be a set of numbers.

LUCKY_DIMON [66]

Answer:

a. closed under addition and multiplication

b. not closed under addition but closed under multiplication.

c. not closed under addition and multiplication

d. closed under addition and multiplication

e. not closed under addition but closed under multiplication

Step-by-step explanation:

a.

Let A be a set of all integers divisible by 5.

Let $x,y$ ∈A such that $x=5m\,,\,y=5n$

Find $x+y,xy$

$x+y=5m+5n=5(m+n)$

So, $x+y$ is divisible by 5.

$xy=(5m)(5n)=25mn=5(5mn)$

So,

$xy$ is divisible by 5.

Therefore, A is closed under addition and multiplication.

b.

Let A = { 2n +1 | n ∈ Z}

Let $x,y$ ∈A such that $x=2m+1\,,\,y=2n+1$ where m, n ∈ Z.

Find $x+y,xy$

$x+y=2m+1+2n+1=2m+2n+2=2(m+n+1)$

So,

$x+y$ ∉ A

$xy=(2m+1)(2n+1)=4mn+2m+2n+1=2(2mn+m+n)+1$

So,

$xy$ ∈ A

Therefore, A is not closed under addition but A is closed under multiplication.

c.

$Let A=\{2,5,8,11,14,...\}$

Let $x=2,y=5$ but $x+y=2+5=7$ ∉A

Also,

$xy=2(5)=10$ ∉A

Therefore, A is not closed under addition and multiplication.

d.

Let A = { 17n: n∈Z}

Let $x,y$ ∈ A such that $x=17n,y=17m$

Find x + y and xy

$x+y=17n+17m=17(n+m)$

$xy=(17m)(17n)=289mn=17(17mn)$

So,

$x+y,xy$ ∈ A

Therefore, A is closed under addition and multiplication.

e.

Let A be the set of nonzero real numbers.

Let $x,y$ ∈ A such that $x=-1,y=1$

Find x + y

$x+y=-1+1=0$

So,

$x+y$ ∈ A

Also, if x and y are two nonzero real numbers then xy is also a non-zero real number.

Therefore, A is not closed under addition but A is closed under multiplication.

4 0

3 years ago

The area of a circle is 286 cm2. Use the π button on your calculator for π in your calculations.

hram777 [196]

Answer:

9.54 cm

Explanation:

area = πr^2

286 cm^2= πr^2

=>πr^2= 286 cm^2

=>r^2= 286÷π

=>r= √286÷π

: 9.54. m

circumference=2πr

=> circumference=2×π×9.54

=60 cm

4 0

3 years ago

The graph of which function will have a maximum and a y-intercept of 4?

stiv31 [10]

Answer:

Step-by-step explanation:

We have quadratic functions f(x) = ax² + bx + c.

c - y-intercept

If a > 0, then a parabola opens up and has a minimum in a vertex.

If a < 0, then a parabola opens down and has a maximum in a vertex.

The function has maximum and y-intercept of 4:

a < 0 and c = 4

4 0

3 years ago