I Need Help I Don't Understand This

Finding a final amount in a word problem on exponential growth or decay

A certain forest covers an area of ^2. Suppose that each year this area decreases by 8.5%. What will the area be after 8 years?
Use the calculator provided and round your answer to the nearest square kilometer.

Answer:

x = -2 + 2√2 i and -2 - 2√2 i

Step-by-step explanation:

Given the function, y=-x^2+4x-12

x intercept occurs at y =  0

Substitute y = 0

0=-x^2+4x-12

x^2 - 4x + 12 = 0

Factorize

x = -4±√4²-4(12)/2

x = -4±√16-48/2

x = -4±√-32/2

x = -4 ± √32 i/2

x = -4+4√2 i/2 and x =-4-4√2 i/2

x = -2 + 2√2 i and -2 - 2√2 i

Answer:

I = PRT where I is the interest, P is the principal deposited/borrowed, R is the rate as a decimal (take the number & divide by 100), and T is time in years.

Answer:

$182000000000

1.82 * 10^11

Step-by-step explanation:

Given that :

Number of engineers = 2.6 million

Average salary = $70,000

Collective income generated by group of engineers yearly :

This will be on average :

2,600,000 * 70,000 = $182000000000

In scientific notation :

$182000000000 = 182 * 1000000000

182 * 1000000000 = 182 * 10^9

182 = 1.82 * 100 = 1. 82 * 10^2

Hence,

$182000000000 = 1.82 * (10^2 * 10^9)

$182000000000 = 1.82 * 10^11

Answer:

36

Step-by-step explanation:

plug in a=3 for a

I belive you meant 99- 7 * a^2

so 99- 7 * (3)^2 = 36

The value of the expression  99 - 7a² for a = 3 is 36.

In mathematics, an expression that incorporates variables, constants, and algebraic operations is known as an algebraic expression.

The given expression is 99 - 7a².

Substitute a = 3 into the given expression:

99 - 7 (3)²

= 99 - 7×9

= 99 - 63

= 36

Hence, the value of the expression  99 - 7a² for a = 3 is 36.

Learn more about algebraic expressions here:

https://brainly.com/question/953809

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2^( 2x - 3 ) = 128

2^( 2x - 3 ) = 2^7

2x - 3 = 7

2x = 10

x = 5

Answer:

x = 5

Step-by-step explanation:

[tex]x^{2x-3} +52 = 180\\x^{2x-3} = 180 -52\\x^{2x-3} = 128\\x^{2x-3} = 2^{7} \\2x-3=7\\2x=10\\x=10/5\\x=5[/tex]

Answer:

3rd option

Step-by-step explanation:

Using the identities

cot x = [tex]\frac{1}{tanx}[/tex]

csc² x = 1 + cot² x

Given

tanθ = [tex]\sqrt{3}[/tex] , then cotθ = [tex]\frac{1}{\sqrt{3} }[/tex]

csc²θ = 1 + ([tex]\frac{1}{\sqrt{3} }[/tex] )² = 1 + [tex]\frac{1}{3}[/tex] = [tex]\frac{4}{3}[/tex]

cscθ = ± [tex]\sqrt{\frac{4}{3} }[/tex] = ± [tex]\frac{2}{\sqrt{3} }[/tex]

Since θ is in 3rd quadrant, then cscθ < 0

cscθ = - [tex]\frac{2}{\sqrt{3} }[/tex] × [tex]\frac{\sqrt{3} }{\sqrt{3} }[/tex] = - [tex]\frac{2\sqrt{3} }{3}[/tex]

Answer:

ii) Find the percentage of boys/girls

Step-by-step explanation:

If im incorrect please comment here ------------》

Answer:

10t+3

Step-by-step explanation:

Answer:

10t+3

Step-by-step explanation:

Answer:

C

Step-by-step explanation:

Answer:

The answer my friend is B.

Answer:

y = (1/2)x + 16

Step-by-step explanation:

General point/slope form is

y = mx +b (the two points given are (4,18) and (16,24))

slope = rise/run = (24-18)/(16-4) = 6/12 = 1/2

y = (1/2)x + b

pick one point (4,18) and plug in

18 = (1/2)4 + b

18 = 2 + b

b = 16 (he still gets $16 for zero chores)

So

y = (1/2)x + 16

[tex]35,867[/tex] ✅

[tex]\large\mathfrak{{\pmb{\underline{\red{Step-by-step\:explanation}}{\orange{:}}}}}[/tex]

[tex]403 \times 89 \\ = 35,867[/tex]

[tex]\large\mathfrak{{\pmb{\underline{\orange{Happy\:learning }}{\orange{.}}}}}[/tex]

Answer:

35867 is the product of 409 and 89. At least I think so.

Step-by-step explanation:

Answer:

x = 16

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Distributive Property

Equality Properties

Algebra I

Step-by-step explanation:

Step 1: Define

Identify

x + (3x - 4) = 5 - (-7 - 3x)

Step 2: Solve for x

Answer:

Q 5.9

Step-by-step explanation:

Que el dinero gastado por Juan sea x

Deja que el dinero gastado por Carolina sea y

Si el dinero total gastado es Q 15

Luego;

x + y = 15 ------- (1)

De la segunda oración;

y = x + 3,2 -------- (2)

Sustituyendo (2) en (1)

x + x + 3,2 = 15

2x + 3,2 = 15

2x = 15 - 3,2

2x = 11,8

x = 5,9

x = Q 5.9

Por lo tanto Juan gastó Q 5.9

Answer:

4 x 3 = 12

2 x 3 = 6

12 + 6 = 18 cubic cm

Answer:b

Step-by-step explanation:

Answer:

[tex]\frac{1}{12}[/tex] or 1:12

Step-by-step explanation:

There are 11 teachers : 132 students

Because ratios are just another way of writing fractions, by putting this into a fraction we get:

[tex]\frac{11}{132}[/tex]

Dividing both the numerator and denominator (top and bottom) by 11, we get:

[tex]\frac{1}{12}[/tex]

Thus, the ratio is [tex]\frac{1}{12}[/tex], or 1:12

Answer:

Step-by-step explanation:bjgnjfvnifcb

Answer:

392.5cm³

Step-by-step explanation:

height of broth in can used= 17-12

= 5cm

Amt. of broth used= πr²h

= 3.14×5²×5

= 392.5cm³

Answer:

The answer is A :)) hehe.

Step-by-step explanation:

Remember, math is a language

when you see per think fractions

15.2 miles per hour = 15.2 miles / 1 hour

since this is a fraction, Units can cancel just like numbers

To cancel miles and be left with hours rearrange the fraction

1 hour / 15.2 miles

then multiply by 72 miles

[tex] \frac{1hour}{15.2miles} \times 72miles[/tex]

the miles cancel and youre left with hours!

so youd write and solve 72 / 15.2

Answer:

1.) Adjacent and form a linear pair

2.) Adjacent and form a linear pair

3.) Adjacent

4.) Not adjacent

Hope this helps!

Answer:

1.) Adjacent and form a linear pair

2.) Adjacent and form a linear pair

3.) Adjacent

4.) Not adjacent

Answer:

135°

Step-by-step explanation:

The arc length is calculated as

EF = circumference of circle × fraction of circle

     = 2πr × [tex]\frac{?}{360}[/tex]

Given EF = 12π , then

2π × 16 × [tex]\frac{?}{360}[/tex] = 12π ( divide both sides by 2π )

16 × [tex]\frac{?}{360}[/tex] = 6 ( multiply both sides by 360 to clear the fraction )

16 ? = 2160 ( divide both sides by 16 )

? = 135°

Answer:

3520 Yards

Step-by-step explanation:

1 Mile = 1760 Yards

Answer: 3520 yards

Step-by-step explanation:

1 mile = 5280 x 2 = 10,560

2miles = 10,560

in yards = 3520 yards

Answer:

2

Step-by-step explanation:

3x+15=21 (the opposite side of parallelogram is equal)

3x=21-15

3x=6

x=6/3

so x=2

AD=2

Answer:

an observational study.

Step-by-step explanation:

An observational study can be defined as a type of study in which a researcher observes and measures the effect of a diagnostic test, risk factors, or treatments on individuals without intervening, changing or manipulating who are or aren't exposed to it (controlled conditions).

In this scenario, a sociologist reviews and analyzes a public park surveillance videos that were randomly selected over a period of several years. From the data obtained, he records the amount of time people spent on a smartphone. Thus, the statistical procedure the sociologist used is called an observational study because he doesn't interfere or manipulate the surveillance video containing information about the amount of time people in the public park spent on their smartphone.

Additionally, an unobtrusive data collection is a data collection technique used mainly in the social sciences to obtain or gather data without the researcher directly interfering or interfacing with the subject being studied. Thus, it doesn't influence the behavior, action or response of the subjects under study.

Answer:

[tex]y = 2 \cos(4x) - 1 \\ when \: y = 0 \\ \cos(4x) = \frac{1}{2} \\ 4x = 60 \\ x = 15 \\ when \: x = 0 \\ y = 2 - 1 = 1 \\ intercepts = > (15, \: 0) \: and \: (0, \: 1) \\ midpoints : ( \frac{15 + 0}{2} , \: \frac{0 + 1}{2} ) \\ = (7.5, \: 0.5) \\ gradient = \frac{1 - 0}{0 - 15} \\ = - \frac{1}{15} \\ y = mx + c \\ at \: (7.5, \: 0.5) \\ 0.5 = - \frac{1}{15} \times 7.5 + c \\ 0.5 = - 0.5 + c \\ c = 1 \\ \therefore \: y = - \frac{1}{15} x + 1 \\ = > 15y = - x + 15[/tex]

Answer: [tex]45.11\ mph[/tex]

Step-by-step explanation:

Given

Speed R varies inversely with time T i.e.

[tex]R\propto \dfrac{1}{T}\\\\R=\dfrac{C}{T}\quad [\text{C=constant}][/tex]

when R=58 mph, T=7 s i.e.

[tex]58=\dfrac{C}{7}\quad \ldots(i)[/tex]

when T=9 s

[tex]R=\dfrac{C}{7}\quad \ldots(ii)[/tex]

Divide (i) and (ii)

[tex]\Rightarrow \dfrac{58}{R}=\dfrac{9}{7}\\\\\Rightarrow R=\dfrac{7}{9}\times 58\\\\\Rightarrow R=45.11\ mph[/tex]

Answer:

29.89%

Step-by-step explanation:

Step 1: We assume that 435 is 100% since it is our output value.  

Step 2: We next represent the value we seek with [tex]$x$[/tex].  

Step 3: From step 1, it follows that [tex]$100\%=435$[/tex].  

Step 4: In the same vein, [tex]$x\%=130$[/tex].  

Step 5: This gives us a pair of simple equations:  

[tex]100\%=435(1)\\\\x\%=130(2)[/tex]  

Step 6: By simply dividing equation 1 by equation 2 and taking note of the fact that both the LHS  (left-hand side) of both equations have the same unit (%); we have  

[tex]$\frac{100\%}{x\%}=\frac{435}{130}$[/tex]  

Step 7: Taking the inverse (or reciprocal) of both sides yields  

[tex]\frac{x\%}{100\%}=\frac{130}{435}\\\\\Rightarrow x=29.89\%[/tex]  

Therefore, [tex]$130$[/tex] is [tex]$29.89\%$[/tex] of [tex]$435$[/tex].

Given:

The figures cylinder, cube, cone, and pyramid.

To find:

The formula of volume for the given figures.

Solution:

Volume of a cylinder is:

[tex]V_1=\pi r^2h[/tex]

Where r is the radius and h is the height.

Volume of a cube is:

[tex]V_2=a^3[/tex]

Where a is side length of cube.

It is also written as:

[tex]V_2=l\times w\times h[/tex]

Where l is length, w is width, h is height and [tex]l=w=h[/tex].

Volume of a cone is:

[tex]V_3=\dfrac{1}{3}\pi r^2h[/tex]

Where r is the radius and h is the height.

Volume of a pyramid is:

[tex]V_4=\dfrac{1}{3}Bh[/tex]

Where B is the base area and h is the height.

Therefore the table of formulae is shown below:

Figure                       Volume formula

Cylinder                   [tex]\pi r^2h[/tex]

Cube                        [tex]l\times w\times h[/tex]

Cone                        [tex]\dfrac{1}{3}\pi r^2h[/tex]

Pyramid                    [tex]\dfrac{1}{3}Bh[/tex]