Help me with this please (khan academy)

Answer: The expression is 7/2.

Answer:

El problema esta incompleto, pero es facil ver que se desea estudiar el enfriamiento de la olla.

Sabemos que la ecuación de enfriamiento de Newton es:

[tex]T (t) = T_s + (T_0 - T_s)*e^{-k*t}[/tex]

Donde t es el tiempo.

[tex]T_s[/tex] es la temperatura del ambiente, en este caso es 12°C

[tex]T_0[/tex] es la temperatura inicial del objeto, en este caso 175°C

k es una constante, que es lo que usualmente se pide obtener en este tipo de problemas.

Reemplazando esos valores en nuestra ecuación obtenemos:

[tex]T(t) = 12 + (175 - 12)*e^{-k*t}\\\\T(t) = 12 + (163)*e^{-k*t}[/tex]

Ahora se nos dice:

"Luego de 10 minutos, la temperatura de la olla será de 100°C"

(estos valores no son necesariamente los del problema, son unos valores genéricos para poder mostrar como se resuelve este tipo de ejercicio)

Entonces, T(10 min) = 100°C

Reemplazando eso en nuestra ecación, obtenemos:

[tex]T(10 min) = 100 = 12 + (163)*e^{-k*10min}[/tex]

Ahora podemos despejar el valor de k resolviendo la ecuación de arriba.

[tex]100 - 12 = (163)*e^{-k*10min}\\\\88 = (163)*e^{-k*10min}\\\\88/163 = e^{{-k*10min}[/tex]

Ahora podemos recordar que:

ln(e^x) = x

Entonces aplicando el logaritmo natural a ambos lados, obtenemos:

[tex]ln(88/163) = ln(e^{-k*10min}) = -k*10min\\\\ln(88/163)/(-10 min) = k = 0.062 min^{-1}[/tex]

Así hemos encontrado el valor de k, y con exactamente el mismo método podríamos encontrar k en cualquier situación de este tipo.

Answer:

4 balls in neither hole, and 6 balls in the smallest hole

Step-by-step explanation:

4 balls in the bigger hole, and 6 balls in neither hole

4(10) + 6(1) = 46

4 balls in the smallest hole, and 6 balls in neither hole

4*100 + 6(1) = 406

4 balls in neither hole, and 6 balls in the smallest hole

4(1) + 6(100) = 604

4 balls in the bigger hole and 6 balls in the smallest hole

4(10)+6(100) = 640

The equation of the circle whose center is (0, 0) and whose radius 5 is x² + y² = 25.

A circle can be characterized by its center's location and its radius's length.

Let the center of the considered circle be at (h,k) coordinate.

Let the radius of the circle be 'r' units.

Then, the equation of that circle would be:

(x-a)²+(y-b)² = r²

Where (a, b) is the centre and 'r' is the radius

We have a circle with centre (0, 0) and radius of 5.

Now, Substituting these value into the equation form, we have

(x-0)²+(y-0)² = 5²

x² + y² = 25

Hence, the equation of the circle whose center is (0, 0) and whose radius 5 is x² + y² = 25.

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This value is 52 million.

===================================================

Explanation:

During the first year, the well produced 50,000 quarts of water per week. Since there are 52 weeks in a year, the well produced 52*50,000 = 2,600,000 quarts in total for that first year alone. This is the initial value 'a'.

The common ratio is r = 1 - 0.05 = 0.95

So we have a geometric sequence with starting term a = 2,600,000 and common ratio r = 0.95

Since -1 < r < 1 is true, we can use the infinite geometric series formula as shown below.

S = a/(1 - r)

S = (2,600,000)/(1-0.95)

S = 52,000,000

S = 5.2 * 10^7 which is choice D

Answer:

Its -34 cuhcuhcuchuchcuh

Step-by-step explanation:

cuhcuhcuchucuhcuhcuhcuhcuchcuh

Answer:

(x + 4) - 3

Step-by-step explanation:

Let the number be x

(x +4) - 3

Answer:

the first difference are all 20.

since the first differences of this relation are constant, it is a linear relation

Answer:

Linear because the account balance increases by a constant 20.

Step-by-step explanation:

→ The first difference is 20 for all values because :

20 - 0 = 20

40 - 20 = 20

60 - 40 = 20

80 - 60 = 20

100 - 80 = 20

Answer:

b -7/8 > -0.50

Step-by-step explanation:

is your answer

Answer:

- 7/8 > -0.50

Step-by-step explanation:

-7/8 =-.875

Change to get decimals with decimals or fractions to have a common denominator

-.875 < -0.60  true

-.875 > -0.50  false

-14/16 > - 15/16 true

-7/8 < - 2/8true

Answer:

a reflection in the y axis followed by a translation 1 unit down

Step-by-step explanation:

Reflection over the y-axis then a unit down

Answer:

The answer is  x = 2y

Step-by-step explanation:

(3x + 2y) (3y + 2 y)

3x = 3y + 2y + 2y

3x = 7y

x = 7 ÷ 3

x = 2y

Answer:

a) 122.5 m ; b) 10 s

Step-by-step explanation:

Just use the given equation and plug in what you know.

a)

d = 4.9t^2

d = 4.9(5^2)

d = 4.9 * 25

d = 122.5 m

b)

d = 4.9t^2

490 = 4.9t^2

100 = t^2

t = 10 s

Answer:

a) 122.5 meters

b) 10 seconds

Step-by-step explanation:

Answer:

[tex]{ \sf{( \sec \theta - \csc \theta)(1 + \tan \theta + \cot \theta) }} \\ = { \sf{( \sec \theta + \tan \theta \sec \theta + \cot \theta \sec \theta) - ( \csc \theta - \csc \theta \tan \theta - \csc \theta \cot \theta)}} \\ = { \sf{( \sec \theta + \sec \theta \tan \theta + \csc \theta) - ( \csc \theta - \sec \theta - \csc \theta \cot \theta)}} \\ = { \sf{ \sec \theta \tan \theta + \csc \theta \cot \theta }} \\ { \bf{hence \: proved}}[/tex]

Answer:

A' (7,-8)

B' (8,-11)

C' (4,-10)

Answered by GAUTHMATH

Answer:

Step-by-step explanation:

A will be 7,-8

B will be 8,-11

C will be 4,-10

How?

add 3 to the x coordinate of the original points and -7 to the y coordinate of the original points, Example: 4+3 = 7 and -1+-7 = -8

Answer:

38º

Step-by-step explanation:

<BAC is a central angle. The corresponding arc, BC will be equal to the measure of the central angle.

So mBC = 38º

Answer:

-71/25

Step-by-step explanation:

We can use the slope formula when given two points

m = (y2-y1)/(x2-x1)

m = (86-15)/(1 -26)

   = 71/-25

  = -71/25

Answer:

[tex]\displaystyle m = \frac{-71}{25}[/tex]

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Algebra I

Step-by-step explanation:

Step 1: Define

Identify

Point (26, 15)

Point (1, 86)

Step 2: Find slope m

Simply plug in the 2 coordinates into the slope formula to find slope m

Answer:

28° because this is an isosceles triangle, and isosceles triangles have congruent base angles.

Answer:

A or 28

Step-by-step explanation:

Cause if both of the sides is 6, than that means that its equal. So 28 on one side and 28 on the other.

Answer:  

x=5  

Step-by-step explanation:

x is the length of the line segment from the center to the boderline of circle. So x=5

Determine the amount of money Kofi earn mowing lawns today

The amount of money Kofi earn mowing lawns today is 30 cedis

Given:

Amount Kofi earn mowing lawns yesterday = 50 cedis

Amount Kofi earn mowing laws today = 60% of yesterday's earning

= 60% of 50 cedis

= 60/100 × 50 cedis

= 0.60 × 50 cedis

= 30 cedis

Therefore, the amount of money Kofi earn mowing lawns today is 30 cedis

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Step-by-step explanation:

the scanned description is very hard to understand.

so I think what happened :

16x² - 9 = 16

then the first error :

sqrt(16x²) - sqrt(9) = sqrt(16)

that is wrong, as you cannot split a + or - operation inside a sqrt function into + or - separate sqrt results of the parts.

so, correctly, the only possible transformation involving sqrt for both sides :

sqrt(16x² - 9) = sqrt(16)

but it would be even easier to clean up the various constant numbers with each other.

so,

16x² - 9 = 16

16x² = 25

and now we trashes the square root

sqrt(16x²) = sqrt(25)

4x = 5

x = 5/4 or x = -5/4

and I cannot see or understand for my life what the second equation was, as Daniel did something wrong, so I cannot deduct the original equation out of a supposedly wrong

y³ - 1 = 7

Answer:

one fourth of 20 = 5

(4+7)-4*5

11-4*5

11-20

-9

Answer:

Step-by-step explanation:

Because those 2 lines are parallel, then 2x + 10 and 2x - 30 are same side interior and are supplementary. Therefore,

2x + 10 + 2x - 30 = 180 and

4x - 20 = 180 and

4x = 200 so

x = 50

Answer:

x = 50

Step-by-step explanation:

Two Parallel lines and an transversal.

Given angles are co - interior angles and they are supplementary.

2x + 10 + 2x - 30 = 180

2x + 2x + 10 -30 = 180   {Combine like terms}

4x - 20 = 180  

4x = 180 + 20     (Add 20 to both sides}

4x = 200              {Divide both sides by 4}

x = 200/4

x = 50

Step-by-step explanation:

starting pt.

root 16²+15²

= 256 + 225

=481

Answer:

C. [tex]4\sqrt{7} -4x\sqrt{7}[/tex] is correct

Steps:

[tex]4\sqrt{7} -3\sqrt{7}x-x\sqrt{7} \\\\4\sqrt{7} -3\sqrt{7} x-\sqrt{7} x\\\\4\sqrt{7} +(-3\sqrt{7} x-\sqrt{7} x)\\\\4\sqrt{7} -4\sqrt{7} x[/tex]

Answer:

C. 4√7 - 4x√7

Step-by-step explanation:

4√7 - 3x√7 - x√7

combine like terms

4√7 - 4x√7

the question is not clear.

Answer: There isn't enough information to answer this

Step-by-step explanation:

so, the time to answer questions has to be added to the speaking time to get the total time of the meeting.

the speaking time is constant (25 minutes).

q = 1 means t = 25 + q = 25 + 1 = 26

q = 2 means t = 25 + q = 25 + 2 = 27

q = 3 means t = 25 + q = 25 + 3 = 28

q = 8 means t = 25 + q = 25 + 8 = 33

Answer:

BC = [tex]\frac{12}{13}[/tex]

Step-by-step explanation:

Using Pythagoras' identity in the right triangle

BC² + AC² = AB²

BC² + ([tex]\frac{5}{13}[/tex] )² = 1²

BC² + [tex]\frac{25}{169}[/tex] = 1 ( subtract [tex]\frac{25}{169}[/tex] from both sides )

BC² = [tex]\frac{169}{169}[/tex] - [tex]\frac{25}{169}[/tex] = [tex]\frac{144}{169}[/tex] ( take square root of both sides )

BC = [tex]\sqrt{\frac{144}{169} }[/tex] = [tex]\frac{12}{13}[/tex]