On a recent quiz, the class mean was 70 with a standard deviation of 2.1. Calculate the z-score (to 4 decimal places) for a person who received score of 76.

Answer:

the coordinate of the focus is: (0, 1/2)

the equation of the directrix is: y=-1/2

Step-by-step explanation: The standard equation for a parabola that opens upward- parallel to the y-axis, is: x2=4ay. Meaning, a = distance from the vertex to focus and the vertex is at origin: (0,0).

4a is equal to 2

a is equal to 2/4

a is equal to 1/2 or 0.5

The parabola has

focus: (0,1/2)

directix: y=-1/2

If the parabola is given by

y=a(x-h)²+k

then the focus of the parabola is given by

(h,k+1/4a)

and the directrix of the parabola is given by

y=k-a

Given parabola is x²=2y

So, the parabola is y=(1/2)x², when compared with y=a(x-h)²+k  we have

a=1/2, h=0 and k=0

So, the focus of the parabola is

[tex](0,\frac{1}{4\frac{1}{2}})= (0,\frac{1}{2})[/tex]

and, the directrix of the parabola is

y= -1/2.

Hence, the parabola has

focus: (0,1/2)

directix: y=-1/2

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I have attached the complete question.

Answer:

See 2nd attachment

Step-by-step explanation:

We are told that R is the solid bounded by the plane z = 5x, the surface z = x², and the planes y = 0 and y = 3.

Thus, the region in the xz plane would be defined as;

0 ≤ x ≤ 3 and x² ≤ z ≤ 5x

For the iterated integral for the volume of the solid R, see 2nd attachment.

Answer:

Step-by-step explanation:

(-13 - 7)/(-1 + 3) = -20/2 = -10

y - 7 = -10(x - 3)

y - 7 = -10x + 30

y =  - 10x + 37

If a factory made 7,737 toy cars each day for 6 days, to find the total number of cars, we can add 7,737 to itself 6 times or just multiply by 6.

[tex]7737*6=46422[/tex]

The factory made 46422 toys in the last 6 days.

Hope this helps.

頑張って!

Answer:

the answer is 200

Step-by-step explanation:it's because

you have to divide 1000 in to 5 and 1000 divided by 5 is 200

Answer:

yes in the steps

Step-by-step explanation:

conclusive

Answer:

5/8

Step-by-step explanation:

The given expression is [tex]\dfrac{x+3y}{6+3y}[/tex]

We need to find of above expression when x = -3 and y = 6

Put x = -3 and y = 6 in given expression such that,

[tex]\dfrac{x+3y}{6+3y}=\dfrac{(-3)+3(6)}{6+3(6)}\\\\=\dfrac{-3+18}{6+18}\\\\=\dfrac{15}{24}\\\\=\dfrac{5}{8}[/tex]

So, the value of given expression is 5/8.

Answer:

Step-by-step explanation:

y + 11 = -8(x - 9)

y + 11 = -8x + 72

y = -8x + 61

The equation of the line in slope-intercept form having the given point and slope is: y = -8x + 61.

Slope-intercept formis expressed as y = mx + b.

Given the following:

A point = (9, -11) = (a, b)

Slope = -8 = m

Substitute m = -8 and (a, b) = (9, - 11) into y - b = m(x - a)

y - (-11) = -8(x - 9)

Rewrite in slope-intercept form

y + 11 = -8x + 72

y = -8x + 72 - 11

y = -8x + 61

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Answer: 198 total people

Step-by-step explanation:

so there are 11 floors and each obtain 9 rooms so if there are two people in each of the 9 rooms there will 18 total people in one floor and since there are 11 floors multiply it by 18 to find out how many people live in the apartment.

11 * 18 = 198

≈ 0,5 m

≈ 50 cm

d = 2r => r = d/2 = 1,4m/2 = 0,7 m

V = πr²·h => h = V/πr²

770 l = 0,77 m³

h = 0,77m³/3.14×0,49m²

= 0,77m³/1,5386m²

= 0,5004 m

≈ 0,5 m

≈ 50 cm

Answer:

LET ME GUESS hmmmm... OH WAIT 30

Step-by-step explanation:

Answer:

30 ft

Step-by-step explanation:

The elm tree is 3 times as tall as the apple tree.

The elm tree is 3 times as tall as 10 ft.

3 * 10 ft = 30 ft

Answer:

D

Step-by-step explanation:

So first you simplify

Step 1: (2•3•7x3y6) (2•3xy6)

Step 2: you divide x3 by x1 = x (3-1) = x2

step 3: You cancel out y6 as it appears on both sides of the fraction line.

step 4: cancel out 2 as it appears on both sides.

step 5: cancel out 3 as it appears on both sides.

step 6: final result 7x2

Answer:

the answer is 65.625, 42 is 64% of 65.625

Answer:

4;3 might be the answer

Answer:

600 %

Step-by-step explanation:

x · 150 ÷ 100 = 900

150x = 90000

x = 600

Answer:

well the length on both increases by x3 and the height increases by 2

Step-by-step explanation:

Answer:

3.5 units

Step-by-step explanation:

I'm big brain

Answer:

answer is 6x+4

mark it as branliest.

Answer:

GK = 6x + 4

Step-by-step explanation:

3x + 5 - x + 4x - 1 - x + x

3x -x + 4x - x + x + 5 -1

6x + 4

Answer:

Explained below

Step-by-step explanation:

Sol: 1. Multiplication

Multiply the set S; the answer should also belong to the set S. For example, -1 x 0 = 0 Є S and -1 x 1 = -1 Є S, Hence the set S is closed under multiplication.

2. Addition

When we add two sets S elements, the answer should also belong to the set S, for example, 1 + 0 = 1 Є S but 1 + 1 = 2, which does not belong to set S; hence S is not closed under addition.

3. Subtraction

The set S is not closed under subtraction because  -1 – 1  = -2, -2 is not the set S.

4. Division

The set S is not a closed division because when we divide one S element to another element, the answer does not belong to the set S, for example -1/0 = undefined.

5. Squaring

The set is closed under squaring if we square an element of the set S, and the result also belongs to the set S, for example, (0)2 = 0 and (-1)2 = 1, which belongs to the set S. Hence set S is closed under squaring.

6. Square rooting

The set S is not closed under square rooting because when we take the square root of an element of set S, the answer does not belong to the set S. √-1 = undefined.

7. Averaging two numbers

Averaging two numbers mean the sum of two numbers of set S is divided by two. For example, 1 + 0/2 = 1/2, which is not belongs to set S. hence set is not closed under averaging two numbers.

8. Averaging three numbers

The sum of three numbers of set S is divided by 3; the answer should belong to the set S.

-1 + 0 + 1 / 3= 0, 0 belongs to set. Hence the set S is closed under averaging three numbers.

Answer is explained below. We can say that Subtraction is not closed under the set.

Given set S = {−1, 0 ,1}  we have to check the given set is closed or not.

1. Multiplication

Multiply the set S; the answer should also belong to the set S. For example, [tex]-1\times 0=0[/tex], 0 Є S and [tex]-1\times 1 = -1[/tex] , -1 Є S, so the set S is closed under multiplication.

2. Addition

On adding the any two values of the set, the result belong to the set itself, for ex if we add [tex]-1+0=-1\\[/tex] Є S  but 1. so we can say that the given set is closed under addition.

3. Subtraction

The set S is not closed under subtraction because  -1 – 1  = -2, -2 is not the set element S.

4. Division

The set S is not belongs to closed division because when we divide one S element to another element, the answer does not belong to the set S, for example -1/0 = undefined.

5. Squaring

The set is closed under squaring,since we square an element of the set S, and the result also belongs to the set S. for example, [tex]0^{2} =0[/tex] and[tex]-1^{2} =1[/tex] which belongs to the set S. Hence set S is closed.

Hence We can say that Subtraction is not closed under the set.

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Answer:

52,500 sq feet

Step-by-step explanation:

150 x 350 = 52,500 sq feet

To find the area, you do width x length.

Hope this helps!!

Answer:

[tex](5,-8)[/tex]

Step-by-step explanation:

The rule for a reflection over the y-axis is

[tex](x,y) -> (-x,y)[/tex]

In this situation, we have to change the sign of x.

[tex](-5,-8) -> (5,-8)[/tex]

Answer:

14-2i

Step-by-step explanation:

[tex]\left(3+5i\right)+\left(11-7i\right)\\\\Group\:the\:real\:part\:and\:the\:imaginary\:part\:of\:the\:complex\:number\\\\\left(a+bi\right)\pm \left(c+di\right)=\left(a\:\pm \:c\right)+\left(b\:\pm \:d\right)i\\\\=\left(3+11\right)+\left(5-7\right)i\\3+11=14\\5-7=-2\\\\=14-2i[/tex]

Answer:

Step-by-step explanation:

2nd train DATA:

time = 2 hrs ; rate = x + 120 mph ; distance = 2(x+120) = 2x+240 miles

------

1st train DATA:

time = 8 hrs ; rate ; x mph ; distance = 8x miles

------------------

Equation:

distance = distance

8x = 2x+240

6x = 240

x = 40 mph (speed of the 1st train)

x+120 = 160 mph (speed of the 2nd train)

my regards #3Ss

Answer:

52

Step-by-step explanation:

everytime it adds by 9:

7+9=16

16+9=25

25+9=34

34+9=43

43+9=52

Answer:

lines that meet at a point

because if you add a zero onto something after the decimal point it doesn't increase or decrease the value of the number.

7.630 is literally just 7.63.

but if it was 76.3 and 760.3 it would be different.

The original price of the iPhone will be $650 thus the buyer saved $78 by buying the refurbished mobile.

The percentage is defined as a given amount in every hundred. It is a fraction with 100 as the denominator percentage is represented by the one symbol %.

The percentage is also called the indicating hundredths. Thus, 2% is two-hundredth, which means 2%=2/100=0.02.

Let's say the original price of the mobile is x.

12% of x is 0.12x

The cost of refurbished mobile will be as x - 0.12x = 0.88x

0.88x = 572

x = $650

The amount saved = $650 - $572 = $78

Hence "The original price of the iPhone will be $650 thus the buyer saved $78 by buying the refurbished mobile".

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Steps to solve:

2(x - 6) = 3(x + 9)

~Distribute both sides

2x - 12 = 3x + 27

~Add 12 to both sides

2x = 3x + 39

~Subtract 3x to both sides

-x = 39

~Divide both sides by -1

x = -39

Best of Luck!

Answer:

2×-12=3×+27

2×-3×=27+12

-×=39

Step-by-step explanation:

Grouping like terms

then simplify to get x