Joylin is writing an equation to model the proportional relationship between y, the total cost in dollars of downloading videos from a website, and x, the number of videos downloaded. She knows that the total cost to download 3 videos was $12. Her work to find the equation is shown below.

Joylin’s Work

Step 1
k = StartFraction 3 over 12 EndFraction = 0.25
Step 2
y = 0.25 x

Where did Joylin make her first error?

Answer:

By comparing of elements of both matrices, we will get,

[tex]x + y = 5 \: \: \: - - - (1) \\ \sf \: and \\ x - 2 = 3 \\ = > x = 3 + 2 \\ = > \green{ \boxed{x = 5}} \\ \\ so \: \: from \: eqn.(1) \\ 5 + y = 5 \\ = > y = 5 - 5 \\ = > \green{ \boxed{ y = 0}}[/tex]

[tex]\large \green{ \: \: \: \: \boxed{\boxed{\begin{array}{cc} \sf \: mark \: \\ me \: as\\ \bf \: brainliest \: \end{array}}}} \\ [/tex]

Answer:

20

Step-by-step explanation:

□□□□□□□□■■■■■■■■■○○○○○

Complete question is;

An online store receives customer satisfaction ratings between 0 and 100, inclusive. In the first 10 ratings the store received, the average (arithmetic mean) of the ratings was 75. What is the least value the store can receive for the 11th rating and still be able to have an average of at least 85 for the first 20 ratings?

Answer:

50

Step-by-step explanation:

We are told that In the first 10 ratings the store received arithmetic mean of the ratings = 75.

Thus;

Sum of the first 10 ratings = 75 × 10 = 750

Now, for the mean of the first 20 ratings to be at least 85, it means that the sum of the first 20 ratings would be; 85 × 20 = 1700

Thus, the sum of the next 10 ratings would be; 1700 − 750 = 950.

If maximum rating = 100, then the maximum possible value of the sum of the 12th to 20th ratings is given by;

9 × 100 = 900.

Now, in order to make the store have an average of at least 85 for the first 20 ratings, the least value for the 11th rating is;

950 − 900 = 50

Answer:

[tex]\displaystyle s = \frac{2ab\cos x}{a+b}[/tex]

Step-by-step explanation:

We want to find a formula for s in terms of a, b, and cos(x).

Let the point where s intersects AB be D.

Notice that s bisects ∠C. Then by the Angle Bisector Theorem:

[tex]\displaystyle \frac{a}{BD} = \frac{b}{AD}[/tex]

We can find BD using the Law of Cosines:

[tex]\displaystyle BD^2 = a^2 + s^2 - 2as \cos x[/tex]

Likewise:

[tex]\displaystyle AD^2 = b^2+ s^2 - 2bs \cos x[/tex]

From the first equation, cross-multiply:

[tex]bBD = a AD[/tex]

And square both sides:

[tex]b^2 BD^2 =a^2 AD^2[/tex]

Substitute:

[tex]\displaystyle b^2 \left(a^2 + s^2 - 2as \cos x\right) = a^2 \left(b^2 + s^2 - 2bs \cos x\right)[/tex]

Distribute:

[tex]a^2b^2 + b^2s^2 - 2ab^2 s\cos x = a^2b^2 + a^2s^2 - 2a^2 bs\cos x[/tex]

Simplify:

[tex]b^2 s^2 - 2ab^2 s \cos x = a^2 s^2 - 2a^2 b s \cos x[/tex]

Divide both sides by s (s ≠ 0):

[tex]b^2 s -2ab^2 \cos x = a^2 s - 2a^2 b \cos x[/tex]

Isolate s:

[tex]b^2 s - a^2s = -2a^2 b \cos x + 2ab^2 \cos x[/tex]

Factor:

[tex]\displaystyle s (b^2 - a^2) = 2ab^2 \cos x - 2a^2 b \cos x[/tex]

Therefore:

[tex]\displaystyle s = \frac{2ab^2 \cos x - 2a^2 b \cos x}{b^2- a^2}[/tex]

Factor:

[tex]\displaystyle s = \frac{2ab\cos x(b - a)}{(b-a)(b+a)}[/tex]

Simplify. Therefore:

[tex]\displaystyle s = \frac{2ab\cos x}{a+b}[/tex]

Answer:

15 boxes were shipped late

Step-by-step explanation:

late = 3% = 0.03

500 x 0.03 = 15 boxes

Answer:

] 14/3 ; ♾ [

Step-by-step explanation:

3x-5>9

3x>9+5

3x>14

x>14/3

wich make it ] 14/3 ; ♾ [

when three times a certain number is subtracted from 5 the result is more than 9 find the number.

Let us assume :

The number be x

Data :

A number is 3 times = 3x

Subtracted from 5

The result = 9

Henceforth, the equation we got is :

Transposing 9 to the other side

Hence, the value of x is 14/3 respectively

Answer:

the answer is three , but let me try to help explain...

in a line the slope (M) as in y=mx + b

is a constant number ... rise over run for every unit in the x direction the y changes by that amount

in your graph what you have to do is locate where the red line crosses the grid in a "nice"  (at the corner of a box).... notice that at the 2 for yards it exactly crosses at the 6 for feet...

that suggests that the "slope", "proportional constant" ,rise over run".

"gradient"  what ever the word you want to use is 6/2 which is 3

Step-by-step explanation:

Answer:

this is a very big number

Step-by-step explanation:

(7000000000)⁷⁰⁰⁰⁰⁰⁰

Answer:

The radius vector is (-8, 7) and (-1 , 5).

Step-by-step explanation:

Determine the radius vector of the midpoint of the segment that is formed by joining the points (-8, 7) and (6, 3).

The end points are (- 8, 7) and (6, 3) .

The mid point is given by

[tex]x = \frac{x' + x''}{2}\\\\y = \frac{y' +y''}{2}\\\\x =\frac{- 8 + 6}{2}=-1\\\\y = \frac{7+3}{2} = 5[/tex]

So, the radius vector is (-8, 7) and (-1 , 5).  

a + 1/b = 5

b + 1/c = 12

c + 1/a = 13

manipulating the first line by subtracting 1/b on both sides

a = 5 - 1/b

manipulating the 3rd line by subtracting 1/a on both sides.

c = 13 - 1/a

plugging a into this

c = 13 -1/(5 -1b)

c = 13 -5 +1/b

c= 8 + 1/b

plugging c into the 2nd line

b + 1/(8 +1/b) = 12

b + 1/8 + b = 12

2b + 1/8 = 12

devide both sides by two

b + 1/16 = 6

b = 11 + 15/16

plugging the value for b into the first line to get a

a + 1/(11 + 15/16) = 5

a + 1/11 + 16/15 = 5

a + 15/165 + 176/165 = 5

a + 191/165 = 5

a = 5 + 191/165

a = 1016/165

plugging b into the 2nd line to get c

11 + 15/16 + 1/c = 12

1/c = 1/16

multiply by c on both sides

1 = 1/16c

multiply by 16 on both sides

16 = c

7^2/7^-2 and (7^2)^2

Answer:

[tex]x - 3[/tex]

Step-by-step explanation:

Given

[tex]Volume = x(x - 3)(x + 4)[/tex]

Required

The shortest side

The volume of a rectangular prism is:

[tex]Volume = Length * Width * Height[/tex]

By comparison, we have:

[tex]Length = x[/tex]

[tex]Width = x-3[/tex]

[tex]Height = x + 4[/tex]

In ascending order, the sides are:

[tex]Width = x-3[/tex]

[tex]Length = x[/tex]

[tex]Height = x + 4[/tex]

This is so because:

Irrespective of the value of x

x - 3 will be less than x

x + 4 will be more than x

Hence, the shortest length is:

[tex]Width = x-3[/tex]

Answer:

b

Step-by-step explanation:

Answer:

21. C, 24.B

Step-by-step explanation:

Since the y-value for x = 0 is not zero, the function cannot have sine in it because sin of 0 is always 0. Therefore, the function will have cos in it. That leaves only B and C left. Since cos(0) is always 1, and the value of y when x = 0 is 0.5, the function will have 1/2 multiplied by a cos function. The only answer option that has that is C.

Now, for the next problem, we know the values of all three sides, and we need to find one angle. We can use the law of cosines for this and plug the values into the equation:

[tex]55^2=40^2+24^2-2(40)(24)\cos(C)[/tex]

We can subtract 40 squared plus 24 squared from both sides to get

[tex]849=-2(40)(24)\cos(C)[/tex]

Negative two times 40 times 24 equals -1920. Dividing -1920 from both sides gets us

[tex]\frac{849}{-1920}=\cos(C)[/tex]

Plugging this equation into a calculator and solving for C, we get the answer as approximately

C = 116.24353.

This rounds to 116.2

Answer:

The conic section for the equation 5x^2 - y = 12 is parabola

Answer:

y=-/+ 4 square root 11

Step-by-step explanation:

is the question is 2(y+4)^2=22 then y=7 but if it is 2(y÷4)^2=22?

Answer:

5/2, 7/3, 9/4, 11/5, 13/6, 15/7,17/8

Step-by-step explanation:

Answer:

2/1

2.5

2whole number6/4

Giá Trị tuyệt đối của  tổng hai số nguyên có hai kết quả là số âm và số dương.Nhưng Giá trị tuyệt đói luôn luôn ra kết quả là số dương nên ta cần kết quả là cả âm và dương khi phá dấu tuyệt đối. khi âm -dương =âm. khi dương- âm=dương

Answer:

11m

I did it by Geometry and used the scale : 1cm represents 5m

Answer:

h = 256 feet

Step-by-step explanation:

Given that,

The initial velocity of firework, v = 128 ft/s

The acceleration due to gravity is-16 ft/s².

We need to find the maximum height reached by the firework.

The equation for the firework is :

[tex]h(t) = -16t^2 + 128t[/tex]

To find the vertex's x-coordinate, we can use  

[tex]t=\dfrac{-b}{2a}\\\\t=\dfrac{-128}{2\times (-16)}\\\\t=4\ s[/tex]

Put all the values in the expression for h (t).

[tex]h(t) = -16(4)^2 + 128(4)\\\\h(t)=256\ ft[/tex]

So, the maximum height reached by the firework is 256 feet.

Answer:

1) 20

2) 60

3) 10

4) 90

Step-by-step explanation:

1. first quartile is the beginning of the box

2. third quartile is the end of the box

3. lowest is the first point of the graph

4. vice versa of 3

Answer:

-3/4

Step-by-step explanation:

First, let's convert the mixed numbers into improper fractions in an effort to make this problem easier to solve.

-2 1/2 as a mixed number is -5/2 and -1 3/4 as a mixed number is -7/4.

Our problem is now -5/2 - (-7/4).

We still can't solve this because the two fractions do not share a common denominator. 4 can serve as one, so -5/2 with a denominator of 4 would be -10/4.

The problem is now -10/4 - (-7/4).

Two negatives make a positive so the problem can be rewritten as -10/4 + 7/4. The final answer is -3/4.

Answer:

False

Step-by-step explanation:

Because the gcf of 10 and 18 is 2

Answer:

False

Step-by-step explanation:

Any factor of a number must evenly devide into the number. 6 does not even divide into 10, so no. The GCF of 10 and 18 is 2.

Answer:

Step-by-step explanation:

The shorter arc is 22 cm.

Arc length formula:

Circumference formula:

Use the first formula to work out the value of C:

Length of arc=L=22cm

We know

[tex]\boxed{\sf L=\dfrac{\Theta}{360}\times πr}[/tex]

[tex]\\ \sf\longmapsto 22=\dfrac{45}{360}\times 2πr[/tex]

[tex]\\ \sf\longmapsto \dfrac{2πr}{8}=22[/tex]

[tex]\\ \sf\longmapsto {2πr=176}[/tex]

[tex]\\ \sf\longmapsto Circumference=176cm[/tex]

Answer:

x = cost of daylily = $12

y = cost of ivy = $2

Step-by-step explanation:

Let

x = cost of daylily

y = cost of ivy

Scott:

12x + 13y = 170

Ashley:

14x + 2y = 172

12x + 13y = 170 (1)

14x + 2y = 172 (2)

Multiply (1) by 14 and (2) by 12

168x + 182y = 2380 (3)

168x + 24y = 2064 (4)

Subtract (4) from (3) to eliminate x

182y - 24y = 2380 - 2064

158y = 316

y = 316/158

y = 2

Substitute y = 2 into (1)

12x + 13y = 170 (1)

12x + 13(2) = 170

12x + 26 = 170

12x = 170 - 26

12x = 144

x = 144/12

x = 12

x = cost of daylily = $12

y = cost of ivy = $2

Answer:

linear. Each week adds another 10 dollars.

Step-by-step explanation:

Total = 340 +  10*w

w is the weekly amount

Suppose 5 weeks pass

Then the total amount in her bank account is

Total = 340 + 10*5

Total = 340 + 50

Total = 390

The equation is Linear.

Answer:

b

Step-by-step explanation:

Answer:

B

Step-by-step explanation:

Each number in the sequence is being multiplied by 4

like this:

1, 4, 16, 64, 256