1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
GarryVolchara [31]
3 years ago
8

The amount of Jen’s monthly phone bill is normally

Mathematics
1 answer:
vredina [299]3 years ago
7 0

Answer:

P(19

And we can find this probability with this difference and using the normal standard distribution

P(-3

Step-by-step explanation:

Let X the random variable that represent the amount of Jen monthly phone of a population, and for this case we know the distribution for X is given by:

X \sim N(55,12)  

Where \mu=55 and \sigma=12

We are interested on this probability

P(19

And we can use the z score formula given by:

z=\frac{x-\mu}{\sigma}

Replacing the info we got:

P(19

And we can find this probability with this difference and using the normal standard distribution

P(-3

You might be interested in
Solve for x 0=3x^2+3x+7​
Aloiza [94]

Answer:

x =(3-√-75)/-6=1/-2+5i/6√ 3 = -0.5000-1.4434i

x =(3+√-75)/-6=1/-2-5i/6√ 3 = -0.5000+1.4434i

Step-by-step explanation:

Rearrange:

Rearrange the equation by subtracting what is to the right of the equal sign from both sides of the equation :

                    0-(3*x^2+3*x+7)=0

Step by step solution:

Step  1:

Equation at the end of step  1  :

 0 -  ((-3x^{2} +  3x) +  7)  = 0  

<u>Step  2:</u>

Pulling out like terms:

2.1     Pull out like factors:

  -3x^{2} - 3x - 7  =   -1 • (3x^{2} + 3x + 7)

Trying to factor by splitting the middle term

2.2     Factoring  3x^{2} + 3x + 7

The first term is,  3x^{2}  its coefficient is  3 .

The middle term is,  +3x  its coefficient is  3 .

The last term, "the constant", is  +7

Step-1 : Multiply the coefficient of the first term by the constant   3 • 7 = 21

Step-2 : Find two factors of  21  whose sum equals the coefficient of the middle term, which is   3 .

     -21    +    -1    =    -22

     -7    +    -3    =    -10

     -3    +    -7    =    -10

     -1    +    -21    =    -22

     1    +    21    =    22

     3    +    7    =    10

     7    +    3    =    10

     21    +    1    =    22

Observation : No two such factors can be found !!

Conclusion : Trinomial can not be factored

Equation at the end of step  3  :

 -3x^{2} - 3x - 7  = 0

<u>Step  3:</u>

Parabola, Finding the Vertex:

3.1      Find the Vertex of   y = -3x^{2}-3x-7

For any parabola,Ax2+Bx+C,the  x -coordinate of the vertex is given by  -B/(2A) . In our case the  x  coordinate is  -0.5000  

Plugging into the parabola formula  -0.5000  for  x  we can calculate the  y -coordinate :

 y = -3.0 * -0.50 * -0.50 - 3.0 * -0.50 - 7.0

or   y = -6.250

Parabola, Graphing Vertex and X-Intercepts :

Root plot for :  y = -3x^{2}-3x-7

Axis of Symmetry (dashed)  {x}={-0.50}

Vertex at  {x,y} = {-0.50,-6.25}

Function has no real roots

Solve Quadratic Equation by Completing The Square

3.2     Solving   -3x^{2}-3x-7 = 0 by Completing The Square .

Multiply both sides of the equation by  (-1)  to obtain positive coefficient for the first term:

3x^{2}+3x+7 = 0  Divide both sides of the equation by  3  to have 1 as the coefficient of the first term :

  x^{2}+x+(7/3) = 0

Subtract  7/3  from both side of the equation :

  x^{2}+x = -7/3

Now the clever bit: Take the coefficient of  x , which is  1 , divide by two, giving  1/2 , and finally square it giving  1/4

Add  1/4  to both sides of the equation :

 On the right hand side we have :

  -7/3  +  1/4   The common denominator of the two fractions is  12   Adding  (-28/12)+(3/12)  gives  -25/12

 So adding to both sides we finally get :

  x^{2}+x+(1/4) = -25/12

Adding  1/4  has completed the left hand side into a perfect square :

  x^{2}+x+(1/4)  =

  (x+(1/2)) • (x+(1/2))  =

 (x+(1/2))2

Things which are equal to the same thing are also equal to one another. Since

  x^{2}+x+(1/4) = -25/12 and

  x^{2}+x+(1/4) = (x+(1/2))2

then, according to the law of transitivity,

  (x+(1/2))2 = -25/12

We'll refer to this Equation as  Eq. #3.2.1  

The Square Root Principle says that When two things are equal, their square roots are equal.

Note that the square root of

  (x+(1/2))2   is

  (x+(1/2))2/2 =

 (x+(1/2))1 =

  x+(1/2)

Now, applying the Square Root Principle to  Eq. #4.2.1  we get:

  x+(1/2) = √ -25/12

Subtract  1/2  from both sides to obtain:

  x = -1/2 + √ -25/12

 √ 3   , rounded to 4 decimal digits, is   1.7321

So now we are looking at:

          x  =  ( 3 ± 5 •  1.732 i ) / -6

Two imaginary solutions :

x =(3+√-75)/-6=1/-2-5i/6√ 3 = -0.5000+1.4434i

 or:

x =(3-√-75)/-6=1/-2+5i/6√ 3 = -0.5000-1.4434i

6 0
3 years ago
Please help will give brainliest
garri49 [273]

Answer:

b = 17

Step-by-step explanation:

For this triangle we have to

a=18.2\\B=62\°\\C=48\°

We want to find the length of b

We know that the sum of the internal angles of a triangle is 180 °

So

A + 62 +48=180\\\\A=180-62-48\\\\A=70\°

Now we use the sine theorem to find the length of b:

\frac{sin(A)}{a}=\frac{sin(B)}{b}=\frac{sin(C)}{c}

Then:

\frac{sin(A)}{a}=\frac{sin(B)}{b}\\\\b=\frac{sin(B)}{\frac{sin(A)}{a}}\\\\b=a*\frac{sin(B)}{sin(A)}\\\\b=(18.2)\frac{sin(62)}{sin(70)}\\\\b=17

5 0
3 years ago
F (x) = |x + 3| -1 . Find the average rate of change from x = -6 to x = 8
Elenna [48]
Average rate of change is (f(8) - f(-6))/(8 - (-6)) = ((<span>|8 + 3| -1) - (</span><span>|-6 + 3| -1))/(8 + 6) = ((</span><span>|11| -1) - (</span><span>|-3| -1))/14 = ((11 - 1) - (3 - 1))/14 = (10 - 2)/14 = 8/14 = 4/7</span>
3 0
2 years ago
Write each of these in scientific notation <br> 1) 0.00000402<br> 2) 1,900,000
Mkey [24]

Answer:

See below in bold.

Step-by-step explanation:

1. 0.00000402

= 4.02 * 10^-6  (Counting the digits after the decimal point until we get to the 4 gives us the -6).

2.  1,900,000

= 1.9 * 10^6    ( counting the number of digits after the 1 gives us 6).

3 0
3 years ago
A side view of a desk telephone is shown below. which of the following is closest to the value of x
mars1129 [50]
The answer should be b.10cm
3 0
3 years ago
Read 2 more answers
Other questions:
  • A jeweler has 5 rings, each weighing 12 g, made of an alloy of 20% silver and 80% gold. She decides to melt down the rings and a
    9·1 answer
  • How do I get the answer y= 2x^2+9x-5
    9·1 answer
  • Sherman Has 3 cats and 2 dogs. Sherman has $22 to spend on pet toys. How much can he spend on each pet? Write your answer as a f
    5·1 answer
  • Which of the following is not true in regard to the benefit of statistics? A. Statistics promotes positive change. B. Statistics
    6·2 answers
  • How to identify the bases and faces of each figure then name the figure
    13·1 answer
  • Write an algebraic expression for the verbal expression, "17 less than k and 12"
    6·1 answer
  • A cinema has 3 screens.last saturday there were 500 visitors
    5·1 answer
  • I need help pls help me
    10·2 answers
  • HI I NEVER KNEW HOW TO DO THIS BUT I DO SO CAN YALL REALLY HELP ME PLEASE
    6·2 answers
  • Johnny measured a city park and made a scale drawing. The soccer field is 6 millimeters wide in the drawing. The actual field is
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!