Help me please im not good at math!

The half-life of the substance is 1.94 years.

The exponential decay formula aids in determining the exponential drop, which is a rapid reduction over time. To calculate population decay, half-life, radioactivity decay, and other phenomena, one uses the exponential decay formula. F(x) = a [tex](1-r)^{x}[/tex] is the general form.

Here

a = the initial amount of substance

1-r is the decay rate

x = time span

The correct form of the equation is given as:

[tex]a=a_{0}[/tex]×[tex](0.7)^{t}[/tex]

where t is an exponent of 0.7 since this is an exponential decay of 1st order reaction

Now to solve for the half life, this is the time t in which the amount left is half of the original amount, therefore that is when:

a = 0.5 a0

Substituting this into the equation:

0.5 [tex]a_{0}=a_{0}[/tex]×[tex](0.7)^{t}[/tex]

0.5 = [tex](0.7)^{t}[/tex]

Taking the log of both sides:

t log 0.7 = log 0.5

t = log 0.5 / log 0.7

t = 1.94 years

The half life of the substance is 1.94 years.

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The value of the vector will be -53. The correct option is C.

In mathematics and physics, the term "vector" is used informally to describe certain quantities that cannot be described by a single number or by a set of vector space elements.

The dot product, also known as the scalar product, is an algebraic operation that takes two sequences of integers of equal length and outputs a single number.

The given vectors are u=2i-9j and v=-5i+7j, the dot product of the vectors will be calculated as below:-

u.v = ( 2i-9j ).( -5i+7j)

u.v = -10i² + 17 (i.j) -45(i.j) -63j²

Substitute i² = 1, j² = 1 and (i.j) = 0 in the above equation.

u.v = -10 + 63

u.v = 53

Therefore, the value of the vector will be -53. The correct option is C.

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The height of the triangle is 11.3 in. The correct option is C. 11.3 in

From the question, we are to determine the height of the given triangle

The height of the given triangle is x in.

Now, we will determine the value of x

In the diagram, we can observe that the height divides the triangle into two equal halves

Thus,

By the Pythagorean theorem, we can write that

12² = x² + 4²

144 = x² + 16

144 - 16 = x²

∴ x² = 144 - 16

x² = 128

x = √128

x = 11.3

Hence, the height of the triangle is 11.3 in. The correct option is C. 11.3 in

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Answer:

76

Step-by-step explanation:

Formula

[tex]\sf Average=\dfrac{\textsf{sum of all the numbers}}{\textsf{amount of numbers}}[/tex]

Given values:

Let x be the score of the fourth test.

To find the score of the fourth test, substitute the given values into the formula and solve for x:

[tex]\begin{aligned} \sf Average & =\dfrac{\textsf{sum of all the numbers}}{\textsf{amount of numbers}}\\\\\implies \sf 80 & = \sf \dfrac{84+78+82+x}{4}\\\sf 80 & = \sf \dfrac{244+x}{4}\\\sf 80 \cdot 4 & = \sf 244 + x \\\sf 320 & = \sf 244 + x\\\implies \sf x & = \sf 320 - 244\\& = \sf 76\end{aligned}[/tex]

Therefore, John scored 76 on his fourth test.

Answer:

Step-by-step explanation:

To graph by hand I would first convert both equations into y=mx+b.

We start with:

[tex]\left \{ {{2x-2y=4} \atop {x+2y=8}} \right.[/tex]

Solve for y for 2x-2y=4

[tex]2x+2y=4\\2y=4-2x\\y=2-x[/tex]

Solve for y for x+2y=8

[tex]x+2y=8\\2y=8-x\\y=4-\frac{x}{2}[/tex]

Giving the new but equal system of equations:

[tex]\left \{ {{y=2x-x} \atop {y=4-\frac{x}{2} }} \right.[/tex]

From this point on you can graph the two functions to find where the two lines intersect, thats your solution.

I've gone ahead and graphed it on desmos for you

Answer:

  140 cm

Step-by-step explanation:

The distance of the foot of the ladder from the building can be found using the Pythagorean theorem (or your knowledge of Pythagorean triples). Once the two distances are found, their difference can be found.

The 650 cm ladder reaches 520 cm up the side of the building. The ratio of these side lengths is 650/520 = 5/4, suggesting these are the sides of a 3-4-5 right triangle. The distance from the building is ...

  (3/5)×650 cm = 390 cm.

Alternatively, the distance (a) from the building can be found using the Pythagorean relation ...

  a² +b² = c²

  a² +520² = 650²

  a = √(422500 -270400) = √152100 = 390 . . . cm

The 650 cm ladder reaches 520 +80 = 600 cm up the side of the building. The ratio of these side lengths is 650/600 = 13/12, suggesting these are the sides of a 5-12-13 right triangle. The distance from the building is ...

  (5/13)×650 cm = 250 cm

Again, the Pythagorean theorem can be used to obtain the same result:

  a = √(422500 -360000) = √62500 = 250 . . . cm

The difference between the two distances is ...

  390 cm -250 cm = 140 cm

The foot of the ladder will be 140 cm closer to the building.

the equation that we can solve using the given system of equations is:

3x^5 - 4x^4 - 11x^3 + 2x^2 - 10x + 15 = 0

Here we have the system of equations:

y = 3x^5 - 5x^3 + 2x^2 - 10x + 4

y = 4x^4 + 6x^3 - 11

Notice that both x and y should represent the same thing in both equations, then we could write:

3x^5 - 5x^3 + 2x^2 - 10x + 4 = y = 4x^4 + 6x^3 - 11

If we remove the middle part, we get:

3x^5 - 5x^3 + 2x^2 - 10x + 4  = 4x^4 + 6x^3 - 11

Now, this is an equation that only depends on x.

We can simplify it to get:

3x^5 - 4x^4 - 11x^3 + 2x^2 - 10x + 15 = 0

That is the equation that we can solve using the given system of equations.

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Answer:

a^2+b^2=c^2

Step-by-step explanation:

leg1=a

leg2=b

hypotenuse=c

a^2+b^2=c^2

Answer:

u see this is how the Pythagorean theorem works a^2 + b^2 = c^ i hope this helps have a great day bye please mark as brainliest :D

Step-by-step explanation:      

The statements which are true regarding the students whose results on 9 tests are as shown are; The median of Nadia's data is equal to the median of Ben's data.

Nadia had the highest score on a test.

According to the task content, it follows that the results of the students in discuss are indicated by means of a box plot as in the attached image.

Consequently, it follows from observation that the median of Nadia and Ben as indicated in the attached box plot is 92 in both cases as indicated by the vertical line in both boxes.

Additionally, the highest score by Nadia is 100 while that for Ben is; 99.

Hence, Nadia had the highest score on a test.

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Answer:

-2/3

Step-by-step explanation:

A rational number is a number that can be expressed as a fraction so when you add 2 fractions it’s a rational number

Answer:

The answer is C

Step-by-step explanation:

Option A is correct. The type of construction that we have here is the bisection of the <D.

The bisection of angle can be defined to be the construction of a ray that would help to divide a particular angle into two equal halves.

In this diagram we can see that the angle here is at D. Hence the construction is aimed at dividing this particular angle into 2. Therefore the answer to the question is The bisection of ∠D.

The bisector does the job of creating an equal measure. The given bisector is known to have the midpoint of the segment. It cuts through this angle and creates two different angles that are of the same size.

If we draw the line in that shape, we will be having the division of that angle. From the explanation here, we can see the answer is the first option

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The completed table will have values filled into it accordingly from left to right and the downwards.

The concept of relative frequencies involves expressing the frequency of occurrence of events as a fraction of a whole frequency.

Hence, it follows that the blank space on the top-leftmost corner of the table can be filled with the value; 4/5 = 0.8.

For the top-rightmost blank space in the table, the required value is; 2/754 = 0.0027.

For the bottom-leftmost blank space, the required value to fill the table is; 1/5 = 0.2.

For the bottom-rightmost blank space, the required value is; 752/754 = 0.9973.

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the weight of the substance after 28 years is 8 grams.

We have that the half life of a substance is defined as the time required for the substance to decrease by half

The formula for calculating the half - life of a material is given as;

[tex]N(t) = N0 (\frac{1}{2} )^\frac{t}{t^\frac{1}{2} }[/tex]

Where

Substitute into the formula

N(t) = 128 × (0. 5) ^28/ 7

N (t) = 128 × ( 0. 5) ^ 4

N(t) = 128 × 0. 0625

N(t) = 8 grams

Thus, the weight of the substance after 28 years is 8 grams.

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Answer:

c=3.

Step-by-step explanation:

∵2*2*2=8,

∴2^3=8.

∵2^c=8,

∴c=3.

The five number summary can be calculated as follows:

lower quartile(Q₁) = 54 + 56 / 2 = 55

Median = 63.5

Upper quartile(Q₃) = 74

Maximum = 80

Interquartile range = Q₃ - Q₁ = 74 - 55 = 19

The five number summary can be found as follows;

48, 50, 54, 56, 63, 63, 64, 68, 74, 74, 79, 80

minimum = 48

lower quartile(Q₁) = 54 + 56 / 2 = 55

The median is the middle number when the data is arranged in ascending or descending order.

Median = 63 + 64 / 2 = 127 / 2 = 63.5

Upper quartile(Q₃)= 74 + 74 / 2 = 148 / 2 = 74

Maximum = 80

Interquartile range = Q₃ - Q₁ = 74 - 55 = 19

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The dataset 78 is an outlier of the dataset

The dataset is given as:

1, 12, 13, 15, 18, 20, 35, 37, 40, 78

Where

Q1 = 13

Q3 = 37

The boundaries of the outliers are given as:

L = Q1 - 1.5 * (Q3 - Q1)

U = Q3 + 1.5 * (Q3 - Q1)

Substitute the known values in the above equation

L = 13 - 1.5 * (37 - 13) = -23

U = 37 + 1.5 * (37 - 13) = 73

This means that the data elements outside the range -23 to 73 are outliers.

78 is outside this range

Hence, 78 is an outlier of the dataset

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625 ml is the amount of smoothie is left for Ahmed to drink.

According to the statement

we have given that the

Ahmed made a 625 ml fruit smoothie in his blender and out of this he gave

320 milliliters of the smoothie to his brother and we have to find that the

How much smoothie is left for Ahmed.

So, For this purpose,

The total smoothie = 625 ml

Smoothie he gave to his brother = 320 ml

Now, we have to find the Amount of smoothie left for ahmed.

So, Smoothie left for ahmed = 625 ml - 320 ml

Smoothie left for ahmed = 305 ml

So, 625 ml is the amount of smoothie is left for Ahmed to drink.

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Question:

Ahmed made a fruit smoothie in his blender, shown below. He gave 320 milliliters of the smoothie to his brother. How much smoothie is left for Ahmed to drink? check the image below.

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Answer:

division

Step-by-step explanation:

ratio compares 2 numbers by dividing them

example

2 out of 3 dentists like gum

2 ÷ 3 = .67 = 67%

so you can say

67% of dentists like gum

A ratio can be defined as the relationship or comparison between two numbers of the same unit to check how bigger is one number than the other one. For example, if the number of marks scored in a test is 7 out of 10, then the ratio of marks obtained to the total number of marks is written as 7:10.

Answer:

Step-by-step explanation:

Comment

There are a number of ways of doing this problem. I don't know which method you are intended to use. One sure way in this case is graphing the equation, I have done this for you. See below. The maximum volume occurs where x = 2

The graph shows that there is a peak at x = 2. That is where the maximum volume is,

Answer

x = 2

Answer:

1 is the closest to 28/31

Step-by-step explanation:

0 is technically 28 spaces away and 1/2 is around 13 spaces away but 1 is only 3. :)

Step-by-step explanation:

its 29 9x4=29 9+4=13 13+4=17

Considering their graphs, the interval in which both functions are positive is:

(0, 2)

A function is positive when it's graph is positioned above the x-axis.

Looking at the graph, the functions are positive for x between 0 and 2, hence the interval in which both functions are positive is stated as follows:

(0, 2)

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7. ∠I and ∠M are corresponding angles.

8. ∠J and ∠P are alternate exterior angles.

9. ∠K and ∠M are alternate interior angles.

10. ∠L and ∠M are consecutive interior angles..

11. ∠I and ∠O are alternate exterior angles.

12. 7. ∠K and ∠O are corresponding angles.

Angles that are formed outside the parallel lines that are intersected by a transversal and lie alternate to each other on along the transversal are alternate exterior angles.

Angles that are formed inside of the parallel lines that are intersected by a transversal and lie alternate to each other on along the transversal are alternate interior angles.

Angles that are formed inside of the parallel lines that are intersected by a transversal and lie on the same side of the the transversal are consecutive interior angles.

Angles that are formed in relative corner position on each of the parallel lines that are intersected by a transversal and lie along the transversal in the same side are called corresponding angles.

Thus, from the image given, we have the following special angles:

7. ∠I and ∠M are corresponding angles.

8. ∠J and ∠P are alternate exterior angles.

9. ∠K and ∠M are alternate interior angles.

10. ∠L and ∠M are consecutive interior angles..

11. ∠I and ∠O are alternate exterior angles.

12. 7. ∠K and ∠O are corresponding angles.

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Answer:

20

Step-by-step explanation:

using the arithmetic progress formula

tn=a+(n-1)d

from the series given above a which is your first term is 50

the d which is the common difference.. you minus the first term from the second term which is 45-50=-5

so the 7th term which our n=7

we have:

t7=50+(7-1)(-5)

t7=50+(6)(-5)

t7=50-30

t7=20

Answer:

a₇ = 20

Step-by-step explanation:

the nth term of an AP is

[tex]a_{n}[/tex] = a₁ + (n - 1)d

where a₁ is the first term and d the common difference

here a₁ = 50 and d = 45 - 50 = - 5 , then

a₇ = 50 + (6 × - 5) = 50 + (- 30) = 50 - 30 = 20

Volume of prism = [tex]\frac{1}{2x^{3} } + x^{2}[/tex]

Given that:

The oblique prism below has an isosceles right triangle base and the length of the base is x

=> the area of the base: [tex]\frac{1}{2}[/tex] × x × x = [tex]\frac{1}{2}[/tex]

The vertical height of the prism is (x + 2)

=> The volume of the oblique prism is:

                    V = the base area * the vertical height

<=> V = [tex]\frac{1}{2}[/tex] [tex]x^{2}[/tex] (x + 2)

<=> V =  [tex]\frac{1}{2x^{3} } + x^{2}[/tex]

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Answer:

175 cal

Step-by-step explanation:

if 12oz = 300 cal

then, 7 oz = ?

cross multiplication

12×?= 7×300

? = 2100/12

? = 175 cal

NB: you can replace the question mark with any variable.

Answer:

174m²

Step-by-step explanation:

SA = 2(wl + hl + hw)

= 2(5m x 11m + 2m x 11m + 2m x 5m)

= 2(55m² + 22m² + 10m²)

= 2 x 87m²

=174m²//

Answer:

a) √80 ≈ 9

b) √27 ≈ 5

c) √110 ≈ 10

d) √0.03 ≈ 0.2

e) √0.12 ≈ 0.3

Step-by-step explanation:

80 is close to 81

Therefore, √80 can be estimated as √81

√81 = 9

[tex]\Large\boxed{\sqrt{80}\approx9 }[/tex]

27 is close to 25

Therefore, √27 can be estimated as √25

√25 = 5

[tex]\Large\boxed{\sqrt{27}\approx5 }[/tex]

110 is close to 100

Therefore, √110 can be estimated as √100

√100 = 10

[tex]\Large\boxed{\sqrt{110}\approx10 }[/tex]

0.03 is close to 0.04

Therefore, √0.03 can be estimated as √0.04

√0.04 = 0.2

[tex]\Large\boxed{\sqrt{0.03}\approx0.2 }[/tex]

0.12 is close to 0.09

Therefore, √0.12 can be estimated as √0.09

√0.09 = 0.3

[tex]\Large\boxed{\sqrt{0.12}\approx0.3 }[/tex]

Hope this helps!! :)

Please let me know if you have any questions

Answer:

A. because 5 < 6. 1-(-4)=5. and 4-(-2) =6