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3 years ago

Simplify the expression: 7r–3r+9r

Mathematics

1 answer:

Arte-miy333 [17]3 years ago

8 0

Answer:

13r

Step-by-step explanation:

all like variables so add the coefficient

7+(-3)+9

7-3+9

=13r

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The ________ is the distance around a circle.

raketka [301]

The answer is circumference

5 0

3 years ago

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A coin is tossed times and comes up heads times. Use the Empirical Method to approximate the probability that the coin comes up

Vedmedyk [2.9K]

Answer:

$P(head) = 0.5600$

Step-by-step explanation:

Given

$n = 500$ -- number of toss

$head = 280$ --- outcomes of head

<em>See comment</em>

Required

Empirical probability of head

This is calculated as:

$P(head) = \frac{n(head)}{n}$

$P(head) = \frac{280}{500}$

$P(head) = 0.5600$

6 0

3 years ago

Use the recursive formula f(n) = 0.4 . f(n-1) + 12 to determine the 2nd term if f(1) = 4.

Irina18 [472]

Answer:

Assuming you have $f(n)=0.4f(n-1)+12$ with $f(1)=4$ , the answer is f(2)=13.6.

Step-by-step explanation:

I think that says $f(n)=0.4f(n-1)+12$ with $f(1)=4$ .

Now we want to find $f(2)$ so replace n with 2:

This gives you:

$f(2)=0.4f(2-1)+12$

$f(2)=0.4f(1)+12$

$f(2)=0.4(4)+12$

$f(2)=1.6+12$

$f(2)=13.6$

5 0

3 years ago

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The weekly earnings of students in one age group are normally distributed with a standard deviation of 47 dollars. A researcher

ELEN [110]

Answer:

Option D) 340

Step-by-step explanation:

We are given the following in the question:

Alpha, α = 0.05

Population standard deviation, σ = $47

Margin of error = 5

95% Confidence Interval:

$\mu \pm z_{critical}\frac{\sigma}{\sqrt{n}}$

$\text{Margin of error} = z_{critical}\frac{\sigma}{\sqrt{n}}$

Putting the values, we get,

$z_{critical}\text{ at}~\alpha_{0.05} = 1.96$

$5 = 1.96(\dfrac{47}{\sqrt{n}} )\\\\\sqrt{n} = \dfrac{47\times 1.96}{5}\\\\n = 339.443776\\\Rightarrow n \approx 340$

Thus, the correct answer is

Option D) 340

7 0

3 years ago

Find the value of x and y. Show all your work neat and<br> in order.

Mazyrski [523]

Answer:

x = 21°

y = 29°

Step-by-step explanation:

a) Solving for x

Note that:

(3x - 3)° and 60° are Alternate interior angles, and alternate interior angles are equal to each other, hence:

3x - 3 = 60° (Alternate interior angles)

Add 3 to both sides

3x - 3 +3 = 60 + 3

3x = 63°

x = 63°/3

x = 21°

b) Solving for y

Notes that:

(3x - 3)° and (4y + 4)° are Consecutive interior angles and the sum consecutive interior angles is 180°

3x - 3 + 4y + 4 = 180°

3x + 4y - 3 + 4 = 180°

3x + 4y + 1 = 180°

Note that x = 21

Hence

3(21) + 4y + 1 = 180°

63 + 1 + 4y = 180°

64 + 4y = 180°

Subtract 64 from both sides

64 - 64 + 4y = 180° - 64

4y = 116°

y = 116/4

y => 29°

8 0

3 years ago