in a 10 team league, each teams play every other team exactly twice. find the total number of games played in the league

Answer:

The value of e is -1 and f is -2.

Step-by-step explanation:

The steps are :

[tex]2e - 3f = 4 - - - (1)[/tex]

[tex]2e - 5f = 8 - - - (2)[/tex]

[tex]2e - 3f - 2e - ( - 5f) = 4 - 8[/tex]

[tex]2f = - 4[/tex]

[tex]f = - 4 \div 2[/tex]

[tex]f = - 2[/tex]

[tex]substitute \: f = - 2 \: into \: (1)[/tex]

[tex]2e - 3( - 2) = 4[/tex]

[tex]2e + 6 = 4[/tex]

[tex]2e = 4 - 6[/tex]

[tex]2e = - 2[/tex]

[tex]e = - 2 \div 2[/tex]

[tex]e = - 1[/tex]

To solve this system of equations by addition, our first goal is to cancel

out one of the variables by adding the two equations together.

However, before we add, we need to cancel out a variable.

I would choose to cancel out the e's.

To do this, we need a 2e and a -2e and

here we have a 2e in both equations.

If we multiply the second equation by -1 however,

that will give us the -2e we are looking for.

So we have (-1)(2e - 3f) = (4)(-1).

So rewriting both equations, our first equation stays the same

but our second equation becomes -2e + 3f = -4.

Notice that every term in the second

equation has been multiplied by -1.

2e - 3f = 4

-2e + 5f = -8

Now when we add the equations together,

the e's cancel and we have 2f = -4 so f = -2.

To find e, plug -2 back in for f in the

first equation to get 2e - 3(-2) = 4.

Solving from here, e = -1.

Note that e comes before f in our final answer, (-1, -2).

To determine which variable should go first

in your answer, use alphabetical order.

Look at where we don't have repeating x values. This happens with function C and function D. All the x values are unique for each choice mentioned.

In choices A, B, and E, the value x = -3 repeats itself. So we don't have a function for either of these. A function is only possible if any input (x) leads to exactly one output (y).

Answer:

(b) the data provide strong evidence that SAT scores are related to learning strategy in the following way: The mean SAT score for students who pay for coaching is higher than mean SAT score for students who study themselves, which in turn is higher than those students who do not study for test.

(c) The data provide strong evidence that the three mean SAT scores (representing the three learning strategies) are not all equal.

Step-by-step explanation:

Relative effectiveness is to study the extent to which an intervention of a thing does more good than harming it when two or more alternative interventions are observed. In the given question the SAT mean score for students who are paying higher for coaching than those student who believe in self study.

Answer:

Unpainted  surface area = 514.28 cm²

Step-by-step explanation:

Given:

Side of cube = 20 Cm

Radius of circle = 20 / 2 = 10 Cm

Find:

Unpainted  surface area

Computation:

Unpainted  surface area = Surface area of cube - 6(Area of circle)

Unpainted  surface area = 6a² - 6[πr²]

Unpainted  surface area = 6[a² - πr²]

Unpainted  surface area = 6[20² - π10²]

Unpainted  surface area = 6[400 - 314.285714]

Unpainted  surface area = 514.28 cm²

Answer:

Here's what I get  

Step-by-step explanation:

a. Net of a cube

Fig. 1 is the net of a cube  

b. Does the formula work?

Tony's formula works if you ignore dimensions.

There are six squares in the net of a cube.

If each side has a unit length s, the total area of the cube is 6s.

c. Will the formula work for any rectangular prism?

No, because a rectangular prism has sides of three different lengths — l, w, and h — as in Fig. 2.

d. Area of a rectangular prism

A rectangular prism has six faces.

A top (T) and a bottom (b) — A = 2×l×w

A left (L) and a right (R)    —   A = 2×l×h

A front (F) and a back (B) —   A = 2×w×h

                                  Total area = 2lw + 2lh + 2wh

If l = 5 m, w = 6 m and h = 8 m,

[tex]\begin{array}{rl}A &=& \text{2$\times$ 5 m $\times$ 6 m + 2$\times$ 5 m $\times$ 8 m + 2 $\times$ 6 m $\times$ 8 m}\\&=& \text{60 m}^{2} + \text{80 m}^{2} + \text{96 m}^{2}\\&=& \textbf{236 m}^{2}\\\end{array}[/tex]

Answer:

  $2587.87 per month

Step-by-step explanation:

The listed deductions are ...

The percentages have a total of ...

  25 +9.3 +6.2 +1.45 +0.9 +5 = 47.85 . . . percent

So, Christine's take-home pay is ...

  $5250(1 -0.4785) -150 = $2587.87 . . . per month

Answer:

0

Step-by-step explanation:

It is not possible to roll a number greater than 6 on a number cube

A probability of 0 means "impossible". This is because a standard number cube (aka a die) has sides labeled 1 through 6. There is no way to roll something larger than 6 on a single die.

Answer: please find the attached files

Step-by-step explanation:

A unit circle formula and special triangle of 45, 30 and 60 degrees can be used to solve the problem.

Please find the attached files for the solution

Answer:

Step-by-step explanation:

Given the set T{X: 2<x ≤ 9} where x is an integer, the element of the set T will be {3, 4, 5, 6, 7, 8, 9}.  note that from the inequality set 2<x ≤ 9, x is not equal to 2 but greater than 2. The inequality can be divided into two as shown;

If 2<x ≤ 9 then 2<x and x≤9

If 2<x, this means x>2 but not equal to 2. This is the reason why 2 is not contained in the set T.

Similarly if x≤9, this shows that x can not be greater than 9 but less than or equal to 9.

Since the set T =  {3, 4, 5, 6, 7, 8, 9}, we are to find n(T). n(T) means cardinality of the set T and cardinality of a set is defined as the total number of element in a set.

Hence n()n(T) = 7 (since there are 7 elements in the set T)

Greetings from Brasil...

a)

Let's just use Pythagoras

L² = X² + (X - 7)²

b)

If L = 13, then what is the value of X ???

L² = 2X² - 14X + 49

2X² - 14X - 120 = 0

X = 12  or  X = - 5

(The distance cannot be negative, so X = 12)

===================================================

Work Shown:

x = starting length of the shadow

y = height of the pole

tan(angle) = opposite/adjacent

tan(58) = y/x

1.6003345 = y/x

1.6003345x = y

x = y/1.6003345

x = (1/1.6003345)y

x = 0.62486936y

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

When the angle changes, the adjacent side gets 90 meters longer

tan(angle) = opposite/adjacent

tan(36) = y/(x+90)

0.72654253 = y/(0.62486936y+90)

0.72654253(0.62486936y+90) = y

0.453994166y + 65.3888277 = y

65.3888277 = y-0.453994166y

65.3888277 = 0.546005834y

0.546005834y = 65.3888277

y = 65.3888277/0.546005834

y = 119.758478075162

y = 119.76

The height of the pole is about 119.76 meters.

Answer:

65dg.

Step-by-step explanation:

Triangles are 180dg.

So 68dg + 47dg = 115dg.

-180dg - 115dg = 65dg.

So the missing length is 65 degrees.

Answer: 65

Step-by-step explanation:

Add both of the numbers on there. Then do 180- that number.

68+47=115

180+115=65

This is because in a triangle all the angles together equal 180.

Answer:

11 meters.

Step-by-step explanation:

The important thing to note here is that the backyard is a square. Since it's a square, all of its sides all equivalent in length. Thus, let's find the length of the sides. To do this, we use the area formula.

The formula for the area of a square is:

[tex]A=n^2[/tex]

Where n is a side. Since we know the area already, we can find n. Find n:

[tex]121=n^2\\n=11[/tex]

Since every side in a square are equivalent, all sides are 11 meters in length.

Therefore, each section of the fence should be 11 meters long.

Answer:

7/8

Step-by-step explanation:

1. Make 1 9/8 into an improper fraction

1 = 8/8

8/8 + 9/8 = 17/8

2. Subtract

17/8 - 11/8 = 7/8

Answer:

The original number could be 85.

Step-by-step explanation:

Let the 2 digits be x and y.

Let the number be xy then, assuming that x is the larger digit:

x - y = 3.

x = y + 3

Also

10y + x + 10x + y = 143

Substituting for x:

10y + y + 3 + 10(y + 3) + y = 143

22y + 33 = 143

22y = 110

y = 5.

So x = y + 3 = 8.

Answer:

➥ 10(x + 3) + x + 10x + x + 3 = 143

➥ 10x + 30 + 12x + 3 = 143

➥ 22x + 33 = 143

➥ 22x = 143 - 33

➥ 22x = 110

➥ x = 110/22

➥ x = 5

The unit digit number = x = 5

The tens digit number = x + 3 = 5 + 3 = 8

The original number = 10(x + 3) + x

The original number = 10(5 + 3) + 5

The original number = 50 + 30 + 5

The original number = 85

Hence,the original number is 85.

Answer:

Step-by-step explanation:

2(75)=150 that's the amount due in total for two months so

400-150= 250 they will owe $250 after two months payment

Answer:

60°

Step-by-step explanation:

A full rotation is 360°. The figure has six sides.

1. Divide

360 ÷ 6 = 60

Each angle of the polygon is 60°. Therefore, the polygon must be rotated at least 60° for the figure to match all sides and vertices.

Answer:

Volume injected  = 1.65 ml

Step-by-step explanation:

mass of Demerol =45 mg.

density of pre-filled in syringe = 50 mg/ml

Volume = 45/50 = 0.9 ml

For atropine mass = 0.3 mg

density= 400 mcg/ml     [ Note : 1 mcg = 0.001 mg]

volume filled  = 0.3/400(0.001) = 0.75 ml

So, the total volume filled = 0.75+0.9 = 1.65 ml

Answer:

  (a)  (x -3)^2 = -6(y +5.5)

Step-by-step explanation:

The equation of a parabola can be written as ...

  (x -h)^2 = 4p(y -k)

where (h, k) is the vertex, and p is the distance from the focus to the vertex.

The vertex is half-way between the focus and directrix, so is ...

  (h, k) = (1/2)((3, -7) +(3, -4)) = (3, -5.5)

The focus is at y=-7, and the vertex is at y=-5.5, so the distance between them is ...

  -7 -(-5.5) = -1.5

Then the equation for the parabola is ...

  (x -3)^2 = 4(-1.5)(y -(-5.5))

  (x -3)^2 = -6(y +5.5) . . . . matches the first choice

Answer:

12t+7w=D

t+w=110

Step-by-step explanation:

12t= $12 made every tutor hour

7w= $7 made every waiter hour

D= total dollars made

t+w=110 is the tutor hour and the waiter hour adding together

Answer:

12t + 7y = x

      or

5t + 770 = x

Step-by-step explanation:

12t + 7y = x

t = number of hours he worked as a tutor

y = number of hours he worked as a waiter

x = the total amount of money he earned

t + y = 110

=> y = 110 - t

=> 12t + 7(110 - t) = x

=> 12t + 770 - 7t = x

=> 5t + 770 = x

Answer:

(x-4)^4=x⁴+4x³(-4)¹+6x²(-4)²+4x¹(-4)³+(-4)⁴

=x⁴-16x³+96x²-256x+256

Answer:

[tex]\displaystyle (s-r)(x) = x^2 - x + 1[/tex]

Step-by-step explanation:

We are given the two functions:

[tex]\displaystyle r(x) = -x^2 + 3x \text{ and } s(x) = 2x + 1[/tex]

And we want to find:

[tex]\displaystyle (s-r)(x)[/tex]

This is equivalent to:

[tex]\displaystyle (s-r)(x) = s(x) - r(x)[/tex]

Substitute and simplify:

[tex]\displaystyle \begin{aligned}(s-r)(x) & = s(x) - r(x) \\ \\ & = (2x+1)-(-x^2+3x) \\ \\ & = (2x+1)+(x^2-3x) \\ \\ & = x^2 +(2x-3x) + 1 \\ \\ & = x^2 - x + 1 \end{aligned}[/tex]

In conclusion:

[tex]\displaystyle (s-r)(x) = x^2 - x + 1[/tex]

Answer:

1: x = -1

2: x = 3

3: x = -3

Step-by-step explanation:

f(x)=x^3+x^2−9x−9

f(x)=x^2(x+1) −9x−9

f(x) = x^2(x+1) - 9(x+1)

f(x)= (x+1)(x^2-9)

f(x) =(x+1)(x-3)(x+3)

Answer:

[tex]\boxed{x=-1, \ x=-3, \ x=3}[/tex]

Step-by-step explanation:

The zeros of a function are the values of x when f(x) = 0.

[tex]x^3 +x^2-9x-9=0[/tex]

Factor left side of the equation.

[tex]x^2(x +1)-9(x+1)=0[/tex]

Take (x+1) common.

[tex](x^2-9)(x+1)=0[/tex]

Set factors equal to 0.

First possibility:

[tex]x^2 -9=0[/tex]

[tex]x^2 =9[/tex]

[tex]x=\± \sqrt{9}[/tex]

[tex]x=\± 3[/tex]

[tex]x=-3 \ \mathrm{or} \ x=3[/tex]

Second possibility:

[tex]x+1=0[/tex]

[tex]x=-1[/tex]

Answer:

20 hours

Step-by-step explanation:

Computer download=5 hours

Computer + Extra processor=4 hours

Computer's rate =1/5 per hour

Computer + extra processor rate=1/4 per hour

Extras processor rate=1/x

Where,

x=how long it takes extra processor to get the job done on its own.

To find x, we have to solve the equation

1/5 + 1/x = 1/4

Subtract 1/5 from both sides

1/5 + 1/x -1/5 = 1/4-1/5

1/x=1/4-1/5

1/x = 5-4/20

1/x = 1/20

Cross product

1(20)=x(1)

20=x

x=20 hours

It would have taken the new extra processor alone 20 hours to download the movie

Answer:

Step-by-step explanation:

Let A= probability it rains

P(A)=0.2

Let B be the probability that the train is late = 0.05

P(B)=0.05

A and B  is A∩B= the probability it rains and the bus is late =0.01

probability pf (A and B)=0.01

7) independent events are related by expression:

A∩B=P(A)*P(B)

       =0.2*0.05=0.01  

check :

p(A|B)=P(A∩B)÷P(B)=0.01/0.05= 0.2

the two event are independent

Answer:

The two are independent.

Step-by-step explanation:

Answer:

V = 60 m³

Step-by-step explanation:

Volume of Triangular Pyramid: V = 1/3bh

Area of Triangle: A = 1/2bh

b = area of bottom triangle (base)

h = height of triangular pyramid

Step 1: Find area of base triangle

A = 1/2(8)(5)

A = 4(5)

A = 20

Step 2: Plug in known variables into volume formula

V = 1/3(20)(9)

V = 1/3(180)

V = 60

Answer:

C

Step-by-step explanation:

13/4 simplified---->3and 1/4

Answer:

1.) 10044

2.) 100.44

Step-by-step explanation:

Since n is a number of five-digit positive integers which are divisible by 36, start multiplying 36 by number. Starting from 278.

Five digits numbers start from multiplying 36 by 278. Any multiplication below 278 by 36 will give four digits numbers.

36 × 278 = 10,008

36 × 279 = 10,044

10,044 tens digit and unit digit equal. Therefore n = 10044

To find n/100, divide 10044 by 100

10044 / 100 = 100.44

Answer:

x= -42

Step-by-step explanation:

put the liketerms together

x+35= -7

x=-35-7

note*the operation sign changes after crossing the equal sign

x= -42