Please help me in this grade 7 percentage question

(A) Positive

When z and y are both positive, the expression{ [tex]\frac{-z}{-y}[/tex] }is equal to [tex]\frac{-z}{-y}[/tex]. Since both z and y are positive, -z is negative and -y is negative, so the expression [tex]\frac{-z}{-y}[/tex] is equal to the positive number [tex]\frac{z}{\\y}[/tex].

Therefore, the sign of {-z}/{-y} when z>0 and y>0 is positive.

So the correct answer is:

(A) Positive

What is sign?

In mathematics, a sign is a symbol that is used to represent the relative size or value of a number or expression. The most common signs used in mathematics are the plus (+) and minus (-) signs, which are used to represent positive and negative numbers, respectively.

For example, the number 5 is a positive number, and it is represented using the plus sign. On the other hand, the number -5 is a negative number, and it is represented using the minus sign.

In addition to the plus and minus signs, there are also other signs used in mathematics, such as the equal sign (=), which is used to indicate that two quantities are equal, and the inequality signs (>, <, ≥, ≤), which are used to indicate that one quantity is greater than or less than another.

Overall, signs play a vital role in mathematics as they help to indicate the size and value of numbers and expressions, and they are essential for performing various mathematical operations and solving mathematical problems.

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1) The growth rate is 40%

2) The number of bacteria initially present is 990

3) The number after four hours is  4904

4) The function in terms of time is written as F(t) = 120e^-1.6t

We know that the number of the bacteria can be obtained on the basis of the function that we have. We know that the process of exponential increase of decrease would have to be modelled by the use of an exponential equation. In this case, we have the equation; n(t) = 990e^0.4t

We know that in this case, the time of the multiplication of the bacterial is t, the percent growth rate of the bacteria is 40% and the initial number of the bacteria is 990.

After 4 hours we have;

n(4) = 990e^0.4(4)

n(4) = 4904

b) Given that the initial temperature  if the system is 120°F and the rate of the cooling is 1.6, the formula is written as;

F(t) = 120e^-1.6t

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Answer: 2

Step-by-step explanation:

The value of each variable iS

x = 6

y = 4

What is angle bisector theorem?

The angle bisector theorem in geometry is concerned with the proportions of the two segments that a line that bisects the opposite angle divides a triangle's side into. It compares their proportional lengths to the proportional lengths of the triangle's other two sides.

Apply the angle bisector theorem to solve for x and y respectively.

✔️4/(9 - x) = 8/x

Cross multiply

4*x = 8(9 - x)

4x = 72 - 8x

Add 8x to both sides

4x + 8x = 72

12x = 72

12x/12 = 72/12

x = 6

✔️y/2 = 6/3

Cross multiply

3*y = 6*2

3y = 12

3y/3 = 12/3

y = 4

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By solving the following trigonometric function of m(x)= x cos(-x) we get m(x) = cos(x).

What is trigonometry ?

Given that;

              m(x) = x cos(-x)

              m(x) = x cos (x)    [ we know that cos(-x) = cos(x) ]

           m(x)/x = x cos(x)/x   [divide both sides by x]

                   m = cos(x)

Therefore, m(x)=x cos(-x) ⇒cos(x)

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Answer: 1/2

Step-by-step explanation:

slope is rise over run (up and down over left to right)

By using the concept of function, it can be calculated that-

(g.f)(x) = 8x - 5

(g - f)(x) = -2x - 5

(g + f)(3) = 13

What is a function?

A function from A to B is a rule that assigns to each element of A a unique element of B. A is called the domain of the function and B is called the codomain of the function.

There are different operations on functions like addition, subtraction, multiplication, division and composition of functions.

Here,

a) The given functions are

   f(x) = 4x

  g(x)= 2x - 5

  (g.f)(x) = g(f(x)) = 2(4x) - 5 = 8x - 5

   (g - f)(x) = g(x) - f(x) = 2x - 5 - 4x = -2x - 5

    (g + f)(x) = g(x) + f(x) = 2x - 5 + 4x = 6x - 5

     (g + f)(3) =  6 [tex]\times[/tex] 3 - 5 = 13

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first off, let's check the equation for each year.

[tex]~~~~~~ \textit{Compound Interest Earned Amount} \\\\ A=P\left(1+\frac{r}{n}\right)^{nt} \quad \begin{cases} A=\textit{accumulated amount}\dotfill & \$736.80\\ P=\textit{original amount deposited}\\ r=rate\to r\%\to \frac{r}{100}\\ n= \begin{array}{llll} \textit{times it compounds per year}\\ \end{array}\dotfill &1\\ t=years\dotfill &4 \end{cases} \\\\\\ 736.80=P\left(1+\frac{\frac{r}{100}}{1}\right)^{1\cdot 4}\implies 736.80=P\left(1+\frac{r}{100} \right)^4 \\\\[-0.35em] ~\dotfill[/tex]

[tex]~~~~~~ \textit{Compound Interest Earned Amount} \\\\ A=P\left(1+\frac{r}{n}\right)^{nt} \quad \begin{cases} A=\textit{accumulated amount}\dotfill & \$788.82\\ P=\textit{original amount deposited}\\ r=rate\to r\%\to \frac{r}{100}\\ n= \begin{array}{llll} \textit{times it compounds per year} \end{array}\dotfill &1\\ t=years\dotfill &7 \end{cases} \\\\\\ 788.82=P\left(1+\frac{\frac{r}{100}}{1}\right)^{1\cdot 7}\implies 788.82=P\left(1+\frac{r}{100} \right)^7 \\\\[-0.35em] ~\dotfill[/tex]

[tex]\stackrel{\textit{using the 1st equation}}{736.80=P\left(1+\frac{r}{100} \right)^4}\implies \cfrac{736.80}{\left(1+\frac{r}{100} \right)^4}=P \\\\\\ \stackrel{\textit{using the 2nd equation}}{788.82=P\left(1+\frac{r}{100} \right)^7}\implies \stackrel{\textit{substituting on the 2nd equation}}{788.82=\cfrac{736.80}{\left(1+\frac{r}{100} \right)^4}\left(1+\frac{r}{100} \right)^7}[/tex]

[tex]788.82=736.80\cfrac{ ~~ \left(1+\frac{r}{100} \right)^7 ~~ }{\left(1+\frac{r}{100} \right)^4}\implies 788.82=736.80\left(1+\frac{r}{100} \right)^3 \\\\\\ \cfrac{788.82}{736.80}=\left(1+\frac{r}{100} \right)^3\implies \sqrt[3]{\cfrac{788.82}{736.80}}=1+\cfrac{r}{100}\implies \sqrt[3]{\cfrac{788.82}{736.80}}=\cfrac{100+r}{100} \\\\\\ 100\sqrt[3]{\cfrac{788.82}{736.80}}=100+r\implies 100\sqrt[3]{\cfrac{788.82}{736.80}}-100=r\implies {\Large \begin{array}{llll} \stackrel{\%}{2.3}\approx r \end{array}}[/tex]

The diagonal of a rectangle with a width of 12 units and a length of 16 units is 20 units

From the question, we are to determine the length of the diagonal of the rectangle

From the given information,

The width of the rectangle is 12 units

and

The length of the rectangle is 16 units,

The diagonal, D, of a rectangle is given by

D = √(l² + w²)

Where l is the length of the rectangle

and w is the width of the rectangle

l = 16

w = 12

Thus,

The diagonal of the rectangle is

D = √(16² + 12²)

D = √(256 + 144)

D = √400

D = 20

Hence, the diagonal is 20 units

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A balloon payment is a one-time, large-scale principal payment made near the end of the loan term.

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Answer:

I believe it is positive although I am not 100% sure.

Step-by-step explanation:

The arrows tend to go upwards even though it does have a curve at the bottom. It is still going upwards.

The diagram that shows a valid approach to the given construction is option a for the perpendicular bisector.

A perpendicular bisector is a section of a line that divides a straight segment into two congruent or equal segments. At exactly its midpoint, they split the line section. With the line segment it divides, a perpendicular bisector produces a 90° angle. A line segment that bisects another line segment at an angle of 90 degrees is referred to as a perpendicular bisector. In other terms, a perpendicular bisector separates a line segment into two equal pieces by intersecting it at a 90° angle. The term "perpendicular bisector" refers to a precise drawing in which a line is accurately divided in half by another line that is perpendicular to the first line. To divide into two equal portions, or bisect, is a verb.

Therefore, The diagram that shows a valid approach to the f=given construction is option a.

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Answer: 2 or 1?

Step-by-step explanation:

3^1 = 3 then 3 - 1 = 2

or 3^(1 - 1) then 3^0 = 1

Answer:

[tex]f(x)=3^{x+1}-3[/tex]

Step-by-step explanation:

The curve of the graph shows it is Exponential:  [tex]f(x)=b^{x-h}+k[/tex]

To find b, h, and k, we need to "un-transform" the graph from  [tex]f(x)=b^{x}[/tex]

1. h = horizontal shift/translation;  k = vertical translation:

  (0,1) ⇒ (-1,-2), so h = -1  and  k = -3  and  [tex]f(x)=b^{x+1}-3[/tex]

2. Given the points (-1,-2), (0,0), and (1,6), use one of them to find b:

     [tex]f(x)=b^{x+1}-3\\0=b^{0+1}-3\\0=b^{1}-3\\3=b^1\\3=b[/tex]

3. Place b, h, and k in their correct places in the function.

0.53.The elements left over after the given set's components have been eliminated from the universal set are the complement of the set.

Explanation:

P(event E)=0.47

Consequently, P(not E)=1P(E) [P(E)+P(not E)=1] =10.47 =0.53

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Answer:

Below

Step-by-step explanation:

$ 5   for the first one   <=== a fixed constant ....admission charge

.25  per minute   <===== charges dependent on the number of minutes

Answer:

pls rate brainliest

Step-by-step explanation:

the entrance fee to the skating rink=$5

each minute the skater uses the rink costs=$0.25

HOPE IT HELPED YOU

1. 177.441177

2. 354.882354

3. 118.294118

4. 473.176472

5. 236.588236

The requested value of f(4) is -10.

What is an expression?

An expression, often known as a mathematical expression, is a finite collection of symbols that are well-formed in accordance with context-dependent principles.

Here, we have

Given:  f(x) =(7x+7, if x ≤ 0

2-3x, if 0 =X, if x ≥ 3

f(4) means the value of f(x) when x = 4.

Which expression on the right applies when x = 4?  

The first one because it applies only when x ≤ 0 and

The last one because it applies when x ≥ 3 and 4 is greater than 3.  The answer is the last expression.

since 4 lies between 0 and greater than

f(4) = 2 - 3(4)

f(4) = -10

Hence, the requested value of f(4) is -10.

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Answer:

1st

Step-by-step explanation:

-400 degrees can also be seen as positive 40 degrees

Answer:

B) Elias sold one-fourth the number of books Lena sold.

Step-by-step explanation:

How is this the answer? Well after I looked at the problem again, I realized what I needed to do. I needed to do 4,832*1/4 which is 1208.

I got this from the line that says "Elias sold 4,832 times one-fourth copies"

I hope this helps!!!!

The volume of the described solid is V = 16r³/3

Given,

A solid line S should be drawn between z=a and z=b. If S has a cross-sectional area of Px through x and is perpendicular to the x-axis, then A (x)

Volume of S = limₙ→∝ ∑i=₁ⁿ A(xi) Δx = [tex]\int\limits^b_a {A(x)} \, dx[/tex]

The equation of circle x² + y² = r² where r is the radius of the circle.

Equation of upper semicircle yu= √(r²-x²)  and

Equation of lower semicircle yl = -√(r²-x²)

Area of cross-section A(x) = (yu² - yl²)

Substitute yu and yl values

A(x) = [√(r²-x²) - (-√(r²-x²) )]² = 4(r² -x²)        (1)

The limit for volume v varies from -r to r

Thus Volume v = ₋[tex]\int\limits^r_r {A(x)} \, dx[/tex]

Substitute A(x) from (1)

V = ₋[tex]\int\limits^r_r {4(r^{2}-x^{2} ) } \, dx[/tex]

⇒V = 4[r²x - x³/3 ]

⇒V = 4(r³ - r³/3) - 4(-r³ + r³/3) = 4[2 (r³ - r³/3)] = 16r³/3

The volume of the described solid S where the base is a circular disk or radius r and parallel cross sections perpendicular to the base are squares is V = 16r³/3

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Answer:

C 76

Step-by-step explanation:

let x = 1st number

let x+ 2 = 2nd number

let x + 4 = 3rd number

let x + 6 = 4th number

Let x + 8 = 5th number

x + x + 2 + x+ 4 + x + 6 + x + 8 = 400  Combine like terms

5x + 20 = 400 Subtract 20 from each side

5x  = 380  Divide both sides by 5

x = 76

Check:

76 + 78 + 80 + 82 + 84 = 400

Answer:

B

Step-by-step explanation:

Assuming these 4 are the only possibilities:

A: This cannot be correct because if 181 were divisible by 9, it would not be prime, as the problem suggests.

C: This cannot be correct because 181/9 is 21.11, which is not a whole number

D: This cannot be correct because 181/3 is 60.333, which is not a whole number

Thus, the answer is B.

FUN FACT:

When seeing whether a number is divisible by 3, add up its digits, and if they are divisible by 3, so is the number. Example: 36 is divisible by 3 because   3 + 6 = 9, and 9 is divisible by 3. 181 is not, however, because 1+8+1=10, and 10 is not divisible by 3.

Same with 9! 459 is divisible by 9 because 4+5+9 = 18, which is divisible by 9. 181 is not, however, because 1+8+1 = 10, which is not divisible by 9.

I hope this helps!

Answer:

B. 181 is prime because its only factors are 1 and itself.

Step-by-step explanation:

Prime number

A whole number greater than 1 that cannot be made by multiplying other whole numbers (its only factors are 1 and itself).  

Prime numbers: 2, 3, 5, 7, 11, 13, 17, 19, 23, etc.

Composite number

A number that is divisible by a number other than 1 and itself (so it has more than 2 factors).  

An example of a composite number is 6 as its factors are 1, 2, 3 and 6.

The factors of 181 are 1 and 181.

Therefore, it is prime because its only factors are 1 and itself.

Answer:

5 i think

Step-by-step explanation:

Answer:

(I will only answer one and I think my explanation can help you understand so you do it yourself) For number 8: the slope-intercept form is: y=-1/3x-11

Step-by-step explanation:

x+3y=-33
3y=-x-33(take away x from both sides of the = sign)

y=-1/3x-11(divide 3 on both sides of the = sign)

Answer:

1= 50

2=1,16

Step-by-step explanation:

because it not have graph

Answer:

Z=3

Step-by-step explanation:

1 1/2+1 1/2= 2+1=3

Answer:

Below

Step-by-step explanation:

WOW! THIS is not 'jogging' :

4 miles / 1/5 hr = 20 m/hr

The band have to sell 76 tickets for each concert to meet the goal

From the question, we have the following parameters that can be used in our computation:

P = 850 + 5x

Also, we have

Bonus = $50

This means that

Cost = 850 + 5x + 50x

So, we have

Cost= 850 + 55x

When they earn $5000, we have

850 + 55x = 5000

Evaluate the like terms

55x = 4150

Divide

x = 76

Hence, the number of tickets is 76

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