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3 years ago

Write a variable expression the the algebraic expression. 3x + 7

Mathematics

1 answer:

frozen [14]3 years ago

8 0

Answer:

Step-by-step explanation:

3x + 7 is both a variable expression and an algebraic expression. Since it is not an equation, we can't "solve for x."

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If an object has an acceleration of 7 m/s, and a mass of 3 kg, what is its force?

Anuta_ua [19.1K]

Answer:

force = 21 kg m/s^2 = 21 N

Step-by-step explanation:

If an object has mass (m) 3 kg, and its acceleration (a) is 7 m/s^2, its force is given by Newton's second law of motion: Force = M * a

Force = 3 kg * 7 m/s^2= 21 kg * m/s^2

This combinations of units (kg * m/s^2) is defined as Newtons in physics and abbreviated "N".

So we can say that the force on this object is of magnitude 21 N

7 0

3 years ago

HELP ASAP WILL GIVE BRAINLIEST IF CORRECT

Anna35 [415]

The expression that can be used is 3.14 (6x4+6^2)

The surface area is 188.4

5 0

3 years ago

Read 2 more answers

Haruka hiked several kilometers in the morning. She hiked only 6 kilometers in the afternoon, which was 25%, percent less than s

Semenov [28]

Answer:

14 km

Step-by-step explanation:

6 km in the afternoon

x km in the morning

6= x- 25%

6= 0.75x

x= 6/0.75

x= 8 km

total 6+8= 14 km

4 0

3 years ago

Plz help out i am so confused

MatroZZZ [7]

Answer:

Me too not trying to get the points but how are u suppose to solve this anyway

Step-by-step explanation:

8 0

3 years ago

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What is the probability that a random person who tests positive for a certain blood disease actually has the disease, if we know

xeze [42]

Answer:

Step-by-step explanation:

Hello!

Any medical test used to detect certain sicknesses have several probabilities associated with their results.

Positive (test is +) ⇒ P(+)

True positive (test is + and the patient is sick) ⇒ P(+ ∩ S)

False-positive (test is + but the patient is healthy) ⇒P(+ ∩ H)

Negative (test is -) ⇒ P(-)

True negative (test is - and the patient is healthy) ⇒ P(- ∩ H)

False-negative (test is - but the patient is sick) ⇒ P(- ∩ S)

The sensibility of the test is defined as the capacity of the test to detect the sickness in sick patients (true positive rate).

⇒ P(+/S) = P(+ ∩ S)

P(S)

The specificity of the test is the capacity of the test to have a negative result when the patients are truly healthy (true negative rate)

⇒ P(-/H) = P(- ∩ H)

P(H)

For this particular blood disease the following probabilities are known:

1% of the population has the disease: P(S)= 0.01

95% of those who are sick, test positive for it: P(+/S)= 0.95 (sensibility of the test)

2% of those who don't have the disease, test positive for it: P(+/H)= 0.02

The probability of a person having the blood sickness given that the test was positive is:

P(S/+)= P(+ ∩ S)

P(+)

The first step you need to calculate the intersection between both events + and S, for that you will use the information about the sickness prevalence in the population and the sensibility of the test:

P(+/S) = P(+ ∩ S)

P(S)

P(+/S)* P(S) = P(+ ∩ S)

P(+ ∩ S) = 0.95*0.01= 0.0095

The second step is to calculate the probability of the test being positive:

P(+)= P(+ ∩ S) + P(+ ∩ H)

Now we know that 1% of the population has the blood sickness, wich means that 99% of the population doesn't have it, symbolically: P(H)= 0.99

Then you can clear the value of P(+ ∩ H):

P(+/H) = P(+ ∩ H)

P(H)

P(+/H)*P(H) = P(+ ∩ H)

P(+ ∩ H) = 0.02*0.99= 0.0198

Next you can calculate P(+):

P(+)= P(+ ∩ S) + P(+ ∩ H)= 0.0095 + 0.0198= 0.0293

Now you can calculate the asked probability:

P(S/+)= P(+ ∩ S) = 0.0095 = 0.32

P(+) 0.0293

I hope it helps!

6 0

3 years ago