please help!! its really hard and i don't understand what my teacher says

The solutions of the quadratic equation 5k² - 20k = 15 will be 4.65 and negative 0.65.

Let the equation be ax² + bx + c = 0.

Then the roots of the equation will be

[tex]\rm x = \dfrac{-b \pm \sqrt{b^2 - 4 a c }}{2a}\\[/tex]

The quadratic equation is given below.

5k² - 20k = 15

Simplify the equation, then we have

k² - 4k = 3

k² - 4k - 3 = 0

Then the roots of the equation will be

[tex]\rm k = \dfrac{ -(-4) \pm \sqrt{(-4)^2 - 4 \times 1 \times (-3) }}{2 \times 1}\\\\k = \dfrac{4 \pm \sqrt {28}}{2}[/tex]

Simplify the equation, then we have

k = (4 ± 5.30) / 2

k = (4 + 5.30) / 2, (4 - 5.30) / 2

k = 4.65, -0.65

The solutions of the quadratic equation 5k² - 20k = 15 will be 4.65 and negative 0.65.

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Answer:

  120 cubes will fill the box

Step-by-step explanation:

You want to know the number of 1-inch cubes it takes to fill a box that is 5 cubes long, 4 cubes wide, and 6 inches tall.

To cover the bottom of the box, Chan needs to make an array of cubes that has 4 rows with 5 cubes in each row. That layer will have ...

  4 × 5 = 20 . . . . cubes per layer

Each layer occupies 1 inch of height, and the box is 6 inches high. The volume of the box will be filled with six of these layers. That will take this many cubes:

  (6 layers) × (20 cubes/layer) = 6 × 20 cubes = 120 cubes

Chan will need 120 cubes to fill the box.

Answer:  2x-5/3=7

Tiger shows you, step by step, how to Isolate x (Or y or z) in a formula

The experimental probability of next person to have Blue eyes is 3/7.

Probability is the branch of mathematics that studies the possible outcomes of given events together with the outcomes' relative likelihoods and distributions.

It is based on the possible chances of something to happen.

Probability (P) = Number of a Favourable outcome {n (E)} / Total number of outcomes {n (S)}  

Simply,  P = n (E) / n (S)

Given, Eye colors of the people

Green = 2

Blue    = 30

Brown = 38

To find the probability of next person to have blue eyes, first we will add the given eye colors

Total number of Eye Colors = 2 + 30 + 38 = 70

Number of Blue Eyes = 30

Then, Probability to have blue eyes P(blue) = Number of Blue Eyes / Total number of Eye Colors

                                                      = 30/70

                                                      = 3/7

So, there is 3/7 chances to next person to have blue eyes.

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Answer:

3/7

Step-by-step explanation:

The average rate of change of f(x) = x - 2√x on the interval [1, 9] is 1/2.

It is a measure of how much the function changed per unit, on average, over that interval.

We have,

f(x) = x - 2√x

On the interval [1,9].

[1, 9] = [a, b]

The average rate of change:

= f(b) - f(a) / b - a

= f(9) - f(1) / 9 - 1

= [(9 - 2√9) - (1 - 2√1)] / 8

= [ (9 - 6) - (1 - 2) ] / 8

= (3 + 1) / 8

= 4 / 8

= 1/2

Thus the average rate of change of f(x) = x - 2√x on the interval [1, 9] is 1/2.

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Answer:

≈67.81

Step-by-step explanation:

Answer:

6

Step-by-step explanation:

The diameter is half of the given radius, therefore, split the radius in half.

[tex]\frac{12\:in^2}{2} = 6\:in^2[/tex]

Answer:

Step-by-step explanation:

Answer:

Step-by-step explanation:

NO x=3

The required expression for the given statement is 4x + 1.

An expression is a number, or a variable, or a combination of numbers and variables and operation symbols.

The given statement is,

the difference between nine times a number and one more than five times the number

Let x be the number.

Thus, we have

nine times a number = 9x

one more than five times the number = 1 - 5x

Thus, the numerical expression we get is

9x + (1 - 5x)

Expanding we get

9x + 1 - 5x

Solving we get

4x + 1

this is the required expression

Thus, the required expression for the given statement is 4x + 1.

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Answer:

40 boxes would weigh 120 pounds. nice

15/45 = 40 x 3 = 120 pounds

Step-by-step explanation:

:)

Using it's concept, the average rates of change are given as follows:

a. 1264.03 soda per person per year.

b. 5851.89 soda per person per year.

c. 128010.89 soda per person per year.

The average rate of change of a function is given by the change in the output divided by the change in the input. Hence, over an interval [a,b], the rate is given as follows:

[tex]r = \frac{f(b) - f(a)}{b - a}[/tex]

For this problem, the function is given as follows:

f(x) = 5.852x^4 - 0.002x³ + 0.006x² + 0.029x + 47.855.

From 1990 to 1996, we have t = 0 to t = 6, hence:

Hence the rate is:

(7632.01- 47.855)/6 = 1264.03.

1264.03 soda per person per year.

From 1990 to 2000, we have t = 0 to t = 10, hence:

Hence the rate is:

(58566.75 - 47.855)/10 = 5851.89.

5851.89 soda per person per year.

From 2005 to 2010, we have t = 15 to t = 20, hence:

Hence the rate is:

(936354.84 - 296300.39)/5 = 128010.89.

128010.89 soda per person per year.

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Miguel uses 300 mL Solution B and 600 mL Solution A.

Let x represent the amount of Solution B used.

2x = the quantity of Solution A used.

Solution A is alcohol = 12%.

Solution B is alcohol = 16%.

Given that 12% = 0.12 and 16% = 0.16, we can calculate the following equation:

2x(0.12) + x(0.16) = 120 (Recall that pure alcohol has a concentration of 100% = 1.00.)

0.24x + 0.16x = 120

0.40x = 120

x = 300 mL

Thus, Miguel  makes use of 300 mL of Solution B and 2(300) = 600 mL of Solution A.

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Answer:

4, 8, 12, 16, 20, 24, 28, 32, 36, and 40 are some multiples of 4 that are positive.

Answer: She can wear 3 outfits to school because

Step-by-step explanation: She is able to wear the pants multiple times so she can have 1 pants 1 shirt 1 tie and 1 jacket for three days

Answer:

x = 24/5

Step-by-step explanation:

Answer:

4a.) 0.0005 = 5 x 10 to the exponent -4

4b.) 0.0025 = 2.5 x 10 to the exponent -3

5a.) 2 x 10 to the exponent -2 = 0.02

5b.) 16 x 10 to the exponent -4 = 0.0016

Tip:

The number being multiplied has to be less than or equal to 10. Count the places the decimal point moves from the end of the number to the number in the original equation.

Example: 0.05 = 5 x 10 to the exponent -2

0.05 has 2 spaces for the decimal point to move up to 5 going right. We use a negative decimal because 0.05 is less than 5. Here is an example where the exponent is positive:

5000 = 5 x 10 to the exponent 3

5000 has 3 spaces for the decimal point to move down to 5 going left.  

Answer: It's the third answer choice.

Step-by-step explanation:

It is the only one that LOOKS like it's reflected over the y-axis (i check the math as well)

Answer:

Tracy paid 40.28 percent of the total price.

Answer:

Slope is 1

Step-by-step explanation:

From the general linear equation:

[tex]{ \rm{y = mx + c}}[/tex]

m is the slope

Comparing with the equation given:

[tex]{ \rm{y = { \green{1}}x - 3}}[/tex]

Answer:

The answer is A

The actual weight of the animal is between 450.2 and 426.2 pounds

An equation is an expression that shows the relationship between two or more numbers and variables.

Inequality can be used to show that two variables or numbers are not equal to each other.

The weight of the larger animals can be off by 12 pounds. Let x represent the actual weight of the animal. If the scale reads 438.2 lbs, hence:

|x - 438.2| = 12

x - 438.2 = 12; or -(x - 438.2) = 12

x = 450.2; or x = 426.2

The actual weight of the animal is between 450.2 and 426.2 pounds

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The points scored by Rodney is 20 points.

The points scored by Justin is 19 points.

x + y = 39 equation 1

x - y = 1 equation 2

Where:

x = points scored by Rodney

y = points scored by Justin

In order to determine the points scored by Justin, take the following steps:

Subtract equation 2 from equation 1 :

2y = 38

Divide both sides of the equation by 2

y = 38/2

y = 19 points

To determine the value of x, substitute for y in equation 2

x - 19 = 1

Combine similar terms: x = 19 + 1

Add similar terms together: x = 20

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Answer:

f(0) = 5, f(7) = 1328, f(-5) = -460

Step-by-step explanation:

[tex]f(x) = 4x^3 - 7x + 5[/tex]

We should substitute the values in the brackets into the equation to find the function's value at that x point.

[tex]f(0) = 4(0)^3 - 7(0) + 5\\\to f(0) = 5[/tex]

[tex]f(7) = 4(7)^3 - 7 \times 7 + 5\\\to f(7) = 4 \times 343 - 49 + 5\\\to f(7) = 1328[/tex]

[tex]f(-5) = 4(-5)^3 - 7(-5) + 5\\\to f(-5) = 4 \times -125 + 35 + 5\\\to f(-5) = -460[/tex]

Answer: AB is twice the size of AC and twice the size of CB

Step-by-step explanation: "Lies between" means that it's in the middle. C is in the middle of A and B. A to C would be the same distance of C to B because C seperates the segments into 2 equal halves. AB is the whole segment including C, you could do AC + AC if you substituted it for the lengths and you would still get AB

The box plots that correctly summarize the data is the option B from the image

This is further explained below.

Generally, a straightforward method of depicting statistical information on a plot, in which a rectangle is used to represent the second and third quartiles of the data, and in which the median value is typically shown by a vertical line drawn within the rectangle.

On each side of the rectangle, there are two horizontal lines that represent the lower quartile and the higher quartile.

A boxplot is a graphical representation of the distribution of data that is based on a summary of five numbers and follows a defined format.

In conclusion, The box plot in the illustration with choice B accurately summarizes the data.

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CQ

Image attached

A group of 15 students were assigned a novel to read during class. The data below represents the number of pages each student read.

8, 8, 10, 11, 12, 12, 13, 14, 16, 16, 18, 18, 18, 20, 24

Which of the following box plots correctly summarizes the data?

A

B.

C.

D

here hope this helps u