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3 years ago

Worth 30 points. Help a homie out

Mathematics

1 answer:

Sauron [17]3 years ago

8 0

Answer:

Multiply the second equation by -3 to get -3x - 9y = -30.

Step-by-step explanation:

When eliminating, you need to find a term with the negative of that term to combine so that they cancel each other out. An example would be 3x in the first equation and (-3x) in another equation so that when added, it becomes: 3x-3x = 0.

In the second equation, you see that there is already an x there and you just need to make it become (-3x). Thus, you multiply the entire second equation by -3 to make -3x. Once you have done that, you can combine the two equations and eliminate 3x from the first equation.

3x + 5y = 30

-3x - 9y = -30

3x + 5y -3x - 9y = 30 + (-30)

0 - 4y = 30 - 30

-4y = 0

<em>You can find y and then x later on from here. </em>

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2.5% of a population are infected with a certain disease. There is a test for the disease, however the test is not completely ac

Aleks04 [339]

Answer:

$P(disease/positivetest) = 0.36116$

Step-by-step explanation:

This is a conditional probability exercise.

Let's name the events :

I : ''A person is infected''

NI : ''A person is not infected''

PT : ''The test is positive''

NT : ''The test is negative''

The conditional probability equation is :

Given two events A and B :

P(A/B) = P(A ∩ B) / P(B)

$P(B) >0$

P(A/B) is the probability of the event A given that the event B happened

P(A ∩ B) is the probability of the event (A ∩ B)

(A ∩ B) is the event where A and B happened at the same time

In the exercise :

$P(I)=0.025$

$P(NI)= 1-P(I)=1-0.025=0.975\\P(NI)=0.975$

$P(PT/I)=0.904\\P(PT/NI)=0.041$

We are looking for P(I/PT) :

P(I/PT)=P(I∩ PT)/ P(PT)

$P(PT/I)=0.904$

P(PT/I)=P(PT∩ I)/P(I)

0.904=P(PT∩ I)/0.025

P(PT∩ I)=0.904 x 0.025

P(PT∩ I) = 0.0226

P(PT/NI)=0.041

P(PT/NI)=P(PT∩ NI)/P(NI)

0.041=P(PT∩ NI)/0.975

P(PT∩ NI) = 0.041 x 0.975

P(PT∩ NI) = 0.039975

P(PT) = P(PT∩ I)+P(PT∩ NI)

P(PT)= 0.0226 + 0.039975

P(PT) = 0.062575

P(I/PT) = P(PT∩I)/P(PT)

$P(I/PT)=\frac{0.0226}{0.062575} \\P(I/PT)=0.36116$

8 0

3 years ago

4.1338 divide by 0.22

Murljashka [212]

I got the answer 18.79

I believe this is correct, Please tell me if im wrong. :)

3 0

3 years ago

Read 2 more answers

Write each number as a product of a decimal number between 1 and 10 and a power of 10.<br> 234,000

MrRa [10]

Answer:

2.34 * 10^5.

Step-by-step explanation:

234000 = 2.34 * 10^5

- there are 5 digits after the first number so the exponent is 5.

4 0

3 years ago

If Y varies directly with X solve the following :

BARSIC [14]

Answer:

a) x = -270

b) y = 304/9 or y = 33.78

c) x = -37.8

Step-by-step explanation:

y varies directly with x so y = kx

y = kx

k = y/x

k = 10/-30 = -1/3

y = -1/3 x

If y = 90 then

90 = -1/3 x

x = 90 *(-3) = -270

k = y/x

k = -19/-4.5

k = 38/9

y = 38/9 x

If x = - 8 then

y = 38/9 *(-8)

y = 304/9 or y = 33.78

k = y/x

k = -4.3 / 12.9

k = - 1/3

y = -1/3 x

If y = 12.6 then

12.6 = -1/3 x

x = 12.6 *(-3)

x = -37.8

5 0

3 years ago

The following table shows the number of goals that the Texas Sharpshooters scored in each of their 8 hockey games this season.

lilavasa [31]

Answer:

Step-by-step explanation:

they have gotten 1 goal in 1/2 (4/8) of their games so they have a 50% chance of getting one goal!

Hope this helps but plz give me brainiest if this is right!

3 0

2 years ago

Read 2 more answers