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3 years ago

1

Mathematics

1 answer:

strojnjashka [21]3 years ago

4 0

Answer:

Step-by-step explanation:

3x - 4y = 13 (1)

2x + y = 5 (2)

——————

3x - 4y = 13

4(2x + y = 5) (2) times 4

——————-

3x - 4y = 13

8x + 4y = 20

——————-

11x = 33

x = 33/11

x = 3

Plug x = 3 in (2):

2(3) + y = 5

6 + y = 5

y = 5-6

y = -1

Thus, x = 3 and y = -1

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An online test of English spelling looked at how well people spelled difficult words. The bar graph to the right shows how many

sweet-ann [11.9K]

Answer:

60 ; 5220

Step-by-step explanation:

A) From the horizontal bar chart provided, it could be inferred that 85 people spell the word 'weird' correctly. The graph is scaled on a fixed interval of 10. Hence, the midpoint of 10 = 5

(80 + 5) = 85

B) In a group consisting of 8719 randomly selected people estimate how many more people can correctly spell weird than inoculate

From the graph :

85 per 100 could spell weird correctly while,

About 25 per 100 could spell inoculate correctly.

Difference In number per 100 people

(85 - 25) = 60 people per 100

We could round 8719 to the nearest 100 = 8700

Number of 100's in 8700 = 8700/100 = 87

(87 × 60) = 5,220 people

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3 years ago

Differentiating Exponential functions In Exercise,find the derivative of the function. See Example 2 and 3.

Keith_Richards [23]

Answer: The derivative would be $f'(x)=2(e^{2x}-e^{-2x})$

Step-by-step explanation:

Since we have given that

$f(x)=(e^x+e^{-x})^{\frac{4}{2}}\\\\f(x)=(e^x+e^{-x})^2$

As we will use "Chain Rule"

and at last we will use the identity '' $a^2-b^2=(a-b)(a+b)$ ''

We need to find the derivative of the function:

$f'(x)=2(e^x+e^{-x})(e^x-e^{-x})\\\\f'(x)=2(e^{2x}-e^{-2x})$

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4 years ago

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3 years ago

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Black_prince [1.1K]

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3 years ago

Read 2 more answers

Phoebe, Andy and Polly share £270.

Stella [2.4K]

*Given
Money of Phoebe - 3 times as much as Andy
Money of Andy - 2 times as much as Polly
Total money of Phoebe, - £270
 Andy and Polly

*Solution

Let
B - Phoebe's money
A - Andy's money
L - Polly's money

1. The money of the Phoebe, Andy, and Polly, when added together would total £270. Thus,

B + A + L = £270 (EQUATION 1)

2. Phoebe has three times as much money as Andy and this is expressed as

B = 3A

3. Andy has twice as much money as Polly and this is expressed as

A = 2L (EQUATION 2)

4. This means that Phoebe has ____ as much money as Polly,

B = 3A
B = 3 x (2L)
B = 6L (EQUATION 3)

This step allows us to eliminate the variables B and A in EQUATION 1 by expressing the equation in terms of Polly's money only.

5. Substituting B with 6L, and A with 2L, EQUATION 1 becomes,

6L + 2L + L = £270
 9L = £270
 L = £30

So, Polly has £30.

6. Substituting L into EQUATIONS 2 and 3 would give us the values for Andy's money and Phoebe's money, respectively.

A = 2L
A = 2(£30)
A = £60

Andy has £60

B = 6L
B = 6(£30)
B = £180

Phoebe has £180

Therefore, Polly's money is £30, Andy's is £60, and Phoebe's is £180.

7 0

3 years ago