A student evaluated −4 + (−9 12) and got an answer of 5 12. What might the student have done wrong? explain in details

Answers

Answer 1

Answer:

[tex]the \: students \: calculation \: was \\ based \:on\: addition \: of \: the \: numbers \\ without \: cosidering \: thier \: nagative \: signs.[/tex]


Related Questions

volume of 29 mL and has a mass of 53 g what’s is the density

Answers

Answer:  1.82

Step-by-step explanation:

Density = [tex]\frac{mass}{volume}[/tex] *Divide the mass by volume.

= 1.82

g The average lifespan for a certain type of vehicle is 8 years and follows an exponential distribution. A lot contains 200 of these vehicles, brand new. What is the probability that 50 or more of them fail in the first 2 years

Answers

Answer:

The probability is [tex]P(A \ge 50 ) = 0.14321[/tex]

Step-by-step explanation:

The average life span is  [tex]\pi = 8[/tex]

The sample size is n =  200

Generally we are told that average lifespan for a certain type of vehicle follows an exponential distribution

i.e  

             [tex]X \~ \ \ \ exp(8)[/tex]

Gnerally the probability distribution function for exponential distribution is

       [tex]f(x) = \left \{ {{\lambda * e^{-\lambda * x }\ \ \ x\ge 0 } \atop {0 \ \ \ \ \ \ \ \ \ \ x < 0}} \right.[/tex]

Now [tex]\lambda[/tex] is the  constant which is evaluated as

      [tex]\lambda = \frac{1}{\pi}[/tex]

=>   [tex]\lambda = \frac{1}{8}[/tex]

=>   [tex]\lambda = 0.125[/tex]

Generally the that the vehicles will fail in less than 2 years is  mathematically represented as

         [tex]P(X \le 2 )= p= \int\limits^2_0 {\lambda e^{- \lambda * x} } \, dx[/tex]

        [tex]P(X \le 2 )= p= [ {0.125 * - \frac{1}{0.125 } e^{- 0.125 * x} } ]|\left 2 } \atop {0}} \right.[/tex]

       [tex]P(X \le 2 )= p= [ {0.125 * - \frac{1}{0.125 } e^{- 0.125 * 2} } ] - [ {0.125 * - \frac{1}{0.125 } e^{- 0.125 * 0} } ][/tex]

     [tex]P(X \le 2 )= p= -0.77880 + 1[/tex]

     [tex]P(X \le 2 )= p= 0.2212[/tex]

Generally the probability that the vehicle will fail in the first 2 years follows a binomial  distribution  with the mean evaluated as

         [tex]\mu = n * p[/tex]

=>      [tex]\mu = 200 * 0.2212[/tex]

=>      [tex]\mu = 44.24[/tex]

The standard deviation is

       [tex]\sigma = \sqrt{np(1 - p)}[/tex]    

      [tex]\sigma = \sqrt{200 * 0.2212 (1 - 0.2212)}[/tex]  

      [tex]\sigma = 5.86[/tex]

Using normal approximation of binomial  distribution the  probability that 50 or more of them fail in the first 2 years is mathematically represented as

   [tex]P(A \ge 50 ) = 1 - P(A < 50 )[/tex]

Applying continuity correction

    [tex]P(A \ge 50.5 ) = 1 - P(A < 50.5 )[/tex]

Here

    [tex]P(A < 50.5 ) = P(\frac{A - \mu }{\sigma} < \frac{50 - 44.24}{5.87} )[/tex]

Generally  

       [tex]\frac{A - \mu }{\sigma} = Z (The \ standardized \ value \ of A )[/tex]

=> [tex]P(A < 50.5 ) = P( Z < 1.0664 )[/tex]

From the z-table the probability value  of  ( Z  <  1.0664   ) is  

     [tex]P( Z < 1.0664 ) = 0.85679[/tex]

So  

   [tex]P(A \ge 50 ) = 1 - 0.85679[/tex]

=> [tex]P(A \ge 50 ) = 0.14321[/tex]

PLEASE HELP MEEEEEEE I NEED THIS QUICK
Which of the following best defines the two quantities that are measured to find the call rate of a phone company? (5 points)
Group of answer choices

The quantity of price measured in dollars depends on the quantity of time measured in minutes.

The quantity of time measured in minutes depends on the quantity of price measured in dollars.

The quantity of time measured in minutes depends on the quantity of speed measured in calls per minute.

The quantity of speed measured in calls per minute depends on the quantity of time measured in minutes.

Answers

Answer:

A: The quantity of the price would be measured in dollars depends on the quantity of time measured in minutes.

Step-by-step explanation:

A seemed like the best answer to me. I hope I helped

3x+2=11 what is the answer

Answers

Answer:

x = 3

Step-by-step explanation:

Hi there !

3x + 2 = 11

3x = 11 - 2

3x = 9

x = 9/3

x = 3

Good luck !

Which is the last operation when evaluating (8-2x)2+4 for x=3?

Answers

Answer:

addition.

Step-by-step explanation:

(8-2x)2+4

(8-2(3))2+4

(8-6)2+4

(2)2+4

4+4 (last operation)

8

Can anyone help me solve for x and y

Answers

x = 24, y = 120

if you disagree tell me, I just substituted values.

Step-by-step explanation:

10. (6x - 7)° + (3x - 29)° = 180°

i.e they are co-interior angles:

6x + 3x - 7 - 29 = 180°

9x - 36° = 180°

9x = 216°

x = 24.

(6x - 7)° = (8y + 17)°

i.e they are vertically opposite angles;

but x = 24.

6(24) - 7 = 8y + 17

144 - 7 = 8y + 17

120 = 8y

y = 15

11. (9x + 25)° = (13x - 19)°

i.e they are corresponding angles;

25 + 19 = 13x - 9x

44 = 4x

x = 11

(13x - 19)° + (17y + 5)° = 180°

i.e they are adjacent angles;

but x = 11

13(11) - 19 +5 + 17y = 180

17y = 180 - 129

17y = 51

y = 3

If g is the midpoint of AB, classify each triangle by its angles and sides

Answers

Each triangle can be classified by its angles and sides in the following ways :

triangle CFE = triangle CFE is a right angle triangle ( as one of its interior angle measures 90° ) . Triangle CFE is also a scalene triangle ( as none of its sides are equal ) .triangle BEC = Triangle BEC is a right angle triangle . It is also a scalene triangle ( as none of its sides or angle are equal ) .triangle BFG = triangle BFG is an equilateral triangle ( all of its sides are equal ) and it is also an acute angle triangle ( all of its angle will be equal to 60° , which is acute ) .triangle GAF = Triangle GAF is an isosceles triangle ( two of its sides - GF and GA are equal ) . It is also an obtuse angled triangle ( one of its angle measures 120° ) .

15 POINTS!

An abandoned lot is to be converted into a community garden. The garden is to consist
of a 7 yard by 20 yard rectangle for planting that is surrounded by a path of uniform
width. The total area of the lot is 198 square yards. What is the width of the path?

SHOW WORK PLS TY

Answers

The answer is 7x20 and that equals 140 good luck

A system of equations is shown.
- x + 3y = 9
x = 1 - 2y
What is the solution of the system?
A. (-19, 10)

B. (-6, 7/10)

C. (-9/2, 9/2)

D. (-3,2)

Answers

Answer:

c

......................

Step-by-step explanation:

.....................

Answer:

c

Step-by-step explanation:

HELP ILL GIVE BRAINLIEST HELPPPP

Answers

EFGH-
Db = 6
Ac = 9

IJKL-
Db = 2
Ac = 3

I hope this helps

Can anybody graph y= —2x + 5.

Answers

Answer:

The y-intercept is 5 so that is where it will start then just keep going down by 2 since the slope is (-2)

hope this helps =3

Plz help ty very much

Answers

Answer:

A fungus breaks down the body of a dead animal or organism.

btw you cant be in college I did this years ago in fourth grade

A fungus breaks down the of a dead animal

If M is the midpoint of AB and AM = 3x -1 and AB =5 x + 2, find x, AM, MB, and AB.

Answers

AB = 2x + 3

Just subtract the 3x - 1 from 5x + 2 = 2x + 3 is AB

x = 2

AB = 12

MB = 7

AM = 5

Hope this helps.

The perimeter, P, of a square whose side length is n.

Answers

Answer: p = 4n

Step-by-step explanation:

To find the perimeter of a shape, you need to add the length of the 4 sides. A square's 4 sides are equal. Therefore, you add n+n+n+n which is the same as 4n.

Answer:

P = n4

Step-by-step explanation:

in order to find the perimeter of an object you must add up all the sides. since we are dealing with a square all the sides are n. so in conclusion, 4 times n would you get you the perimeter, P.

mike is 46 yrs old. He is 4 yrs older than 3 times his son Jared's age. Find Jared's age

Answers

Answer:

Jared is 14 years old

Step-by-step explanation:

What is the average speed of a baseball that is thrown 90 feet in 2 seconds?
A. 180 feet/second
B. 45 feet/second
C. 92 feet/second
D. A variable most often found on the y-axis

Answers

B. 45 feet/second

To find out how fast it can go in 1 second, we divide it by 2
90 divided by 2 is 45, so the average speed of a baseball that is thrown 90 feet in 2 seconds is 45 feet/second
For this answer is b

Simplify -√36 please

Answers

Answer:

-6

Step-by-step explanation:

djhcjici4n c rncinr

for the question the answer will be -6

1/2 mi = 880 yd
O True
O False



Help

Answers

Answer:

True

Step-by-step explanation:

1,760 yds = 1 mile, 1,760 ÷ 2 = 880

What is the equation of the line in slope-intercept form? the line perpendicular to y = x + 2 through (-7, -8)​

Answers

Answer:

[tex]y=-x-15[/tex]

Step-by-step explanation:

Point-slope formula: [tex]y-y_1=m(x-x_1)[/tex], where [tex](x_1, \ y_1)[/tex] are the coordinates of a point on the line, and [tex]m[/tex] is the slope of the line.

You are given a point that the line you are trying to find passes through, and a slope. The slope is less obvious than the point, but you can find the slope using the given information.

The line perpendicular to y = x + 2 will have the opposite reciprocal slope of this line. The slope of y = x + 2 is 1, so the opposite reciprocal of 1 is:

[tex]m=-\frac{1}{1} =-1[/tex]

Now that you have both a point and the slope of the line you are trying to find, you can substitute these values into the point-slope formula (Notice: the name of this formula contains both "point" and "slope").

Substitute [tex](-7, \ -8)[/tex] for [tex](x_1,\ y_1)[/tex] and [tex]m=-1[/tex] into the point-slope formula.

[tex]y-(-8)=-1(x-(-7))[/tex]

Simplify this equation.

[tex]y+8=-1(x+7)[/tex]

Distribute -1 inside the parentheses.

[tex]y+8=-x-7[/tex]

Subtract 8 from both sides of the equation.

[tex]y=-x-15[/tex]

This line is in slope-intercept form ([tex]y=mx+b[/tex]), so we are done.

CAN SOMEONE PLEASE DOUBLE CHECK IF THIS IS RIGHT!!! Please

Answers

Answer:

yes yesss yessssssssssssssssssssssssssssssssssss

2x+ 8y = -3
3x+ 6y = -4
Choose all answers that apply

Answers

multiply the top equation by 3, multiply the bottom equation by 4, then subtract the bottom equation from the top equation

multiply the top equation by 3, multiply the bottom equation by -2, then add the equations

What are the x and y-intercepts from the table shown?​

Answers

X intercept is -4,0 and Y is 0,8
X- intercept is -4,0
Y- intercept is 0,8

ve spent the whole weekend grading math assignments. I graded 30 students
work this weekend, which is 40% of my class. How many students do I have in
my class?

Answers

Answer:

75

Step-by-step explanation:

How many students is 1% of the class, 30/40=0.75, so you could do 0.75x100=75, or you could do 0.75x60=45, and 45+30=75.

A=4 b= -5 and c=-8
HELLPPPPPP

Answers

-13:)

Hope this helps
I got -3.

since b = -5, that cancels out the negative and makes b=5.

5+-8 is -3.

Round 47.58051 to the nearest thousandths

Answers

Answer:

47.581

Step-by-step explanation:

can't explain I just know how to do it

Can someone please help me!!! Also does anyone know if there is a website or calculator that may give me the answers? Please help me! Thank you!

Answers

Answer:

[tex] x = 17 [/tex]

Step-by-step explanation:

[tex] 2x + 7 = 3x - 10 [/tex] (alternate exterior angles are congruent when a transversal cuts across two straight lines)

[tex] 2x - 3x = -7 - 10 [/tex] (collecting like terms)

[tex] - x = -17 [/tex]

[tex] \frac{-x}{-1} = \frac{-17}{-1} [/tex] (dividing both sides by -1)

[tex] x = 17 [/tex]

Maggie bought a pound of bananas and 4 boxes of cereal for $10.11. If each box of cereal cost $2.40, what was the price of a pound of bananas?
$0.51
$0.61
$1.51
$2.91

Answers

Answer:

$0.51

Step-by-step explanation:

If each box of cereal is $2.40, $2.40 multiplied by 4 is $9.60. $10.11 is the total, so $10.11 - $9.60 = $0.51.

Answer:

$0.51

Step-by-step explanation:

the person above me was correct

Someone, please help me.

Answers

I believe the answer would be four since the right and left side are symmetrical, same as the top and bottom

Annabel wants to buy a $50.00 jacket that is marked 30% off. What is the final cost of the jacket (after the discount)?

Question 1 options:

$15.00


$35.00


No Solution


$65.00

Answers

Answer:

$ 35.00

Step-by-step explanation:

50.00 ÷ 10 = 5.00 (10%)

5.00 x 3 = 15.00 ( 30%)

50 - 15 = 35.

Sorry I couldn't explain more, But I hope this helps!

If f(x) = 8x+9 and g(x) = 4x-3, what is (f+g)(x)?
O A 4x-12
B. 4x+12
0
C 12x+6
D. 32x-27

Answers

I think is c that what i think
I think it’s c that’s what I think
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Berry asked.11 Several years ago in Indiana, a Department of Education lawyer suggested that allowing advertisements on buses would invite First Amendment challenges by spurned advertisers, the group noted.12 Berry said the bill would limit the types of advertising that would be allowed.13 The regulations would prohibit ads that contain obscene or sexual material, or messages associated with gambling, tobacco products, alcohol, and political campaigns or causes. The ads could not promote drug use or any illegal activity or antisocial behavior. 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