Plsss help this is hard giving 20 pnts!!!

The concentration of H⁺ ions at a pH of 7 is 1 x 10⁻⁷ M.

Ion concentration refers to the amount of ions that are present in a solution or a medium, expressed in terms of their concentration.

The concentration of ion with pH of 7 is calculated as follows;

pH = -log[H⁺]

[H⁺] = 10^(-pH)

The given pH = 7, so the ion concentration is calculated as;

[H⁺] = 10⁻⁷

[H⁺]  = 1 x 10⁻⁷ M

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Answer:

Step-by-step explanation:

Sin O= opp/hyp

Sin 55 = BC/AB

Sin 55=.82

so

BC/AB=.82

Answer:

y = -5x + 31

Step-by-step explanation:

To find the equation of a line parallel to the line 5x + y = 5, we first need to rearrange it in slope-intercept form, which is

y = -5x + 5. (We see that the slope of this line is -5)

A line parallel to this line will have the same slope of -5. Now, we need to find the equation of a line that passes through the point (8,-9) with slope -5.

We can use the point-slope form of the line to find the equation. The point-slope form of a line is given by y - y1 = m(x - x1), where (x1, y1) is a point on the line and m is the slope of the line.

Substituting the values we have, we get:

y - (-9) = -5(x - 8)

Simplifying this equation, we get:

y + 9 = -5x + 40

y = -5x + 31

Therefore, the equation of the line parallel to 5x + y = 5 that passes through the point (8, -9) is y = -5x + 31.

Answer:

(1/2)(12)(16) + (1/2)π(6^2)

= (96 + 18π) square cm

= about 152.55 square cm

The actual speed (along the road) of the red car is 8.37 feet per second

Let's call the distance between the police car and the red car "x" at time t. Then, we know that:

x^2 = 40^2 + (140 - vt)^2

Where

We are given that dx/dt (the rate at which x is decreasing) is -85 ft/s, so:

d/dt [x^2] = d/dt [40^2 + (140 - vt)^2]

2x(dx/dt) = 0 - 2v(140 - vt)

Substituting dx/dt = -85 and solving for v, we get:

2x(−85) = −2v(140−vt)

−170x = −280v + 2v^2t

v^2t = 140v - (85/2)x

Now, we can differentiate the equation x^2 = 40^2 + (140 - vt)^2 with respect to time to get:

2x(dx/dt) = 2(140 - vt)(-v)

Substituting dx/dt = -85 and solving for x, we get:

-170x = -2v(140 - vt)

x = (140v - vt^2)/85

Substituting this expression for x into the equation we derived earlier, we get:

v^2t = 140v - (85/2)((140v - vt^2)/85)

v^2t = 140v - 70(2v - t^2)

v^2t = 140v - 140v + 70t^2

v^2t = 70t^2

v = sqrt(70t^2)/t = sqrt(70) = 8.37 ft/s (rounded to two decimal places)

Therefore, the actual speed (along the road) of the red car is 8.37 feet per second

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Answer:

8 13/15

Step-by-step explanation:

Multiply the fractions so they both have the least common denominator:

5 2/3 = 5 10/15

3 1/5 = 3 3/15

Now, you can add the two mixed numbers:

[tex]5 \frac{10}{15} + 3 \frac{3}{15} = 8 \frac{13}{15}[/tex]

This is your final answer.

Answer: V=1578.28 m³

Step-by-step explanation:

Volume is given as the formula

[tex]V=\frac{2}{3}\pi r^{3}[/tex]

r, radius, is the line from the center point to any end of the semi-sphere(that's what this shape is called) Here they show radius as

r=9.1

Substitute r into the formula

[tex]V=\frac{2}{3}\pi (9.1)^{3}[/tex]    plug into calculator

V=1578.275    round to hundredths means 3 digits after the decimal point

V=1578.28  the number after the 7 is 5 or greater so you round up.

Answer:

Step-by-step explanation:

The possible outcomes for the coin toss being tails and the card chosen being 1, 2, or 3 are:

-T1

-T2

-T3

Therefore, there are three possible outcomes for the event that the coin toss is tails.

Answer:

Equation:  250(1 + 0.028t) = 500

Answer:  36 years

Step-by-step explanation:

The equation we can use to solve this problem is the simple interest formula:

[tex]\boxed{A = P (1 + rt)}[/tex]

where:

Given the initial investment is $250 at an interest rate of 2.8%, and Edward wants to double his money:

Substite these values into the equation:

[tex]500=250(1+0.028t)[/tex]

Swap sides:

[tex]250(1+0.028t)=500[/tex]

Now solve for t:

[tex]\implies \dfrac{250(1+0.028t)}{250}=\dfrac{500}{250}[/tex]

[tex]\implies 1+0.028t=2[/tex]

[tex]\implies 1+0.028t-1=2-1[/tex]

[tex]\implies 0.028t=1[/tex]

[tex]\implies \dfrac{0.028t}{0.028}=\dfrac{1}{0.028}[/tex]

[tex]\implies t=35.71428571...[/tex]

Assuming the interest is applied annually on the anniversary of the account opening, it will take Edward 36 years to double his money with a 2.8% simple interest rate.

The solution to the given simultaneous equation y = -x + 10 ; y = -x + 12 is zero.

y = -x + 10

y = -x + 12

Subtract both equations

y - y = -x -(-x) + 10 -12

0 = -x + x - 2

0 = 0 - 2

0 = -2

In conclusion, zero is the solution to the equation

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If the "y-value" is decreasing at rate of 2 units per second, the rate at which "x" is changing when x=3/2 is -1/3 units per second.

The point moves along a curve having equation as : y = 2x² + 1; and

We know that y is decreasing at a rate of 2 units per second. We have to find the rate at which "x" is changing when x = 3/2,

To solve this problem, we differentiate, the curve equation,

So, taking the derivative of both sides of the equation with respect to time "t",

We get,

⇒ d/dt (y) = d/dt (2x² + 1),

⇒ dy/dt = (4x) × dx/dt,

We are given that dy/dt = -2 (since y is decreasing at a rate of 2 units per second), and we need to find "dx/dt" when x = 3/2,

Substituting "x = 3/2" and "dy/dt = -2",

We get,

⇒ -2 = 4×(3/2)(dx/dt),

⇒ -2 = (6)×(dx/dt),

⇒ dx/dt = -1/3,

Therefore, the rate at which "x" is changing when x = 3/2 is -1/3 units per second.

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The given question is incomplete, the complete question is
A point moves along a curve y=2x² + 1 in such a way that the y value is decreasing at the rate of 2 units per second. At what rate is x changing when x= 3/2 ?

The graph of the equation is linear

Given data ,

In physical education class, students get one sticker for each mile they walk and two stickers for each mile they run.

And , Jenny earned nine stickers

and completed seven miles

Based on the information provided, Jenny earned 9 stickers and completed 7 miles in physical education class. She receives one sticker for each mile she walks and two stickers for each mile she runs.

We can represent this information on a graph with the number of stickers earned on the vertical axis (y-axis) and the number of miles completed on the horizontal axis (x-axis).

Hence , the graph is solved

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Answer:

The area should be 0.5 * b * h

Step-by-step explanation:

B stands for the base of the triangle and H is the height

Answer:

see below

Step-by-step explanation:

L = 2W-6

given: (L+3)*(W+3) = 270

so (2W-6+6)*(W+6) = 270

so 2W*(W+6) = 270

open up the brackets

2w²+12W = 270

so solve quadratic equations of 2w²+12W - 270 =0

w = 9 or -15

so dimensions of the unframed photograph = width 9, length 12

Carmine's loan balance after two years would be approximately $13,827.72.

In mathematics, the term "loan" typically refers to a sum of money that is borrowed by one party from another with the agreement to repay it with interest over time. Loans are a common financial concept used in various areas of mathematics, such as finance, economics, and business.

"Compounded quarterly" refers to a method of calculating interest or investment growth where the interest is added to the principal and then reinvested or recalculated at the end of each quarter (every three months) within a given time period.

To calculate Carmine's loan balance after two years, we need to use the compound interest formula, which is given by:

A = P ×[tex](1+r/n)^{nt}[/tex]

Where:

A = the loan balance after t years

P = the initial principal amount (loan amount) = $11,500

r = annual interest rate = 8% or 0.08 (expressed as a decimal)

n = number of times interest is compounded per year = 4 (since it is compounded quarterly)

t = time in years = 2 (since Carmine made no payments for the first two years)

Putting the values into the formula, we get:

A = 11,500 × (1 + 0.08/4)⁸

A = 11,500 × (1 + 0.02)⁸

A = 11,500 × (1.02)⁸

A ≈ $13,827.72

So, Carmine's loan balance after two years would be approximately $13,827.72.

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Step-by-step explanation:

When we simplify the expression -5/9 - (-9/4), we can rewrite it as:

-5/9 + 9/4

To add these fractions, we need to find a common denominator. The least common multiple of 9 and 4 is 36, so we can convert both fractions to have a denominator of 36:

-5/9 = -20/36

9/4 = 81/36

Now we can substitute these values into our expression and add them:

-20/36 + 81/36 = 61/36

Therefore, the simplified expression is 61/36.

The value of x is 18.4 and the value of y is 22.5 in the cube

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

The diagram of a cube.

Each edge of the cube = 13 units.

The diagonal of each face is x units long

So, we have

x^2 = 13^2 + 13^2

Evaluate

x = 18.4

The diagonal of the cube is y units long.

So, we have

y^2 = 13^2 + 13^2 + 13^2

Evaluate

y = 22.5

Hence, the value of x is 18.4 and the value of y is 22.5

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Answer: 61,6 in.

Step-by-step explanation:

To find the area of trapezoids with parallel bases, we add the length of the lower base to the length of the upper base.

Then we multiply this value by the height.

Finally, we divide the resulting value by [tex]2[/tex].

The scatter plot that has a pattern that is best fit by y = x^2 has a property that displays a nonlinear pattern

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

Equation of the best fit of the scatter plot: y = x^2

As a general rule

Any equation that has a degree other than 1 is a non linear equation

This means that the property it displays is a nonlinear pattern

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The height of the Ferris wheel at point A is 100 ft.

The height of the Ferris wheel at  point B is 182.1 ft.

The height of the Ferris wheel at  point C is 39.9 ft.

The height of the Ferris wheel at each point is calculated as follows;

The height of a point on a circle; H = h + y

Where;

H = h + rsinθ

where;

For point A with θ = 0 radians;

H = 100 + 85 x sin (0)

H = 100 ft

For point B with θ = 7π/12 radians;

H = 100  + 85 x sin(7π/12)

H = 182.1 ft

For point C with θ = 5π/4 radians;

H = 100  + 85 x sin(5π/4)

H = 39.9 ft

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Answer:

B. 200 students

Step-by-step explanation:

Answer: No.

Step-by-step explanation:

The graph doesn't represent a linear, exponential, or quadratic function.

An example of a linear function is a straight line.

An example of a quadratic function is like a smile.

An example of an exponential function is a curved line.

So hence, this doesn't represent a function.

Reply below if you have any questions of concerns.

You're welcome!

- Nerdworm

The amount(volume) of water that will be needed to fill the pool is 144 ft³.

Volume is the space occupied by a solid shape.

To calculate the amount(volume) of water that will be needed to fill the pool, we use the formula below

Formula:

Where:

From the diagram in the question,

Given:

Substitute these values into equation 1

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the distance between line t and point D(-7, 0) is approximately 3.5 units.

what is distance  ?

Distance is a measure of the amount of space between two objects or points. It is usually measured in units such as meters, kilometers, miles, or feet. Distance can be either a scalar quantity

In the given question,

To find the distance between line t and point D(-7, 0), we need to first find the point on line t that is closest to point D.

We can use the formula for the distance between a point and a line in the coordinate plane:

distance = |Ax + By + C| / √(A^2 + B^2)

where Ax + By + C is the equation of the line in standard form, and (x, y) is the coordinates of the point.

In this case, the equation of line t is y = -x - 2, which we can rewrite in standard form as x + y + 2 = 0.

Using the formula above, we have:

distance = |x + y + 2| / √(1^2 + (-1)^2)

distance = |(-7) + 0 + 2| / √(2)

distance = 5 / √(2)

distance ≈ 3.5 (rounded to the nearest tenth)

Therefore, the distance between line t and point D(-7, 0) is approximately 3.5 units.

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Answer:

378in^2 i think

Step-by-step explanation:

Let's start by setting up some equations to represent the given information.

Let's say the price of a postcard is "x" cents.

Then, according to the problem statement, the price of an envelope is 8 times cheaper than the notepad, which means the price of an envelope is (1/8)th of the price of the notepad. So the price of an envelope is (1/8)*y cents, where "y" is the price of the notepad in cents.

Also, we know that the price of an envelope is 2 cents more expensive than the price of a postcard, so we can write:

(1/8)*y = x + 2 ...(Equation 1)

We also know that there are 15 postcards and 10 envelopes in the purchase, so the total cost of the postcards and envelopes is:

15x + 10[(1/8)*y] ...(Equation 2)

Finally, we have a notepad that costs "y" cents. So the total cost of the purchase is:

15x + 10[(1/8)*y] + y ...(Equation 3)

We are given that the total cost of the purchase is 1 dollar and 68 cents, which is equal to 168 cents. So we can write:

15x + 10[(1/8)*y] + y = 168 ...(Equation 4)

Now we have four equations (Equation 1, Equation 2, Equation 3, and Equation 4) with three variables (x, y, and 168). We can solve for x and y by using a system of equations.

From Equation 1, we can solve for y in terms of x:

(1/8)*y = x + 2

y = 8x + 16

Substituting this expression for y into Equations 2 and 3, we get:

15x + 10[(1/8)*y] = 15x + 10(8x + 16) = 160x + 160

15x + 10[(1/8)*y] + y = 15x + 8x + 16 = 23x + 16

Substituting these expressions into Equation 4, we get:

23x + 16 = 168

Solving for x, we get:

x = 6

Substituting this value for x into Equation 1, we can solve for y:

(1/8)*y = x + 2 = 6 + 2 = 8

y = 64

So the price of a postcard is 6 cents, the price of an envelope is (1/8)*64 + 2 = 10 cents, and the price of a notepad is 64 cents

Step-by-step explanation:

Let X be the amount invested at 6%, Y be the amount invested at 9%, and Z be the amount invested at 13%.

From the problem, we know that:

X + Y + Z = 7600 ---(1) (the total amount invested is $7600)

0.06X + 0.09Y + 0.13Z = 818 ---(2) (the total income from the investments is $818)

Z = X + Y + 1200 ---(3) (the amount invested at 13% is $1200 more than the amounts invested at 6% and 9% combined)

We can use equation (3) to substitute for Z in equations (1) and (2), then solve for X and Y as follows:

X + Y + (X + Y + 1200) = 7600

2X + 2Y = 6400

X + Y = 3200

0.06X + 0.09Y + 0.13(X + Y + 1200) = 818

0.06X + 0.09Y + 0.13X + 0.13Y + 156 = 818

0.19X + 0.22Y = 662

Using the system of equations X + Y = 3200 and 0.19X + 0.22Y = 662, we can solve for X and Y to get:

X = 800

Y = 2400

Substituting back into equation (3), we get:

Z = X + Y + 1200 = 4400

Therefore, the amounts invested at 6%, 9%, and 13% were $800, $2400, and $4400 respectively.