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2 years ago

Ella completed the following work to test the equivalence of two expressions. '

Mathematics

1 answer:

Romashka [77]2 years ago

8 0

Answer:

The expressions are not equivalent because Ella did not know that you can’t use substitution to test for equivalence.

Step-by-step explanation:

Equivalent algebraic expressions are those expressions which on simplification give the same resulting expression.

Two algebraic expressions are said to be equivalent if their values obtained by substituting any values of the variables are same.

Two expressions 3f+2.6 and 2f+2.6 are not equivalent, because when f=1,

3f+2.6=3.1+2.6=3+2.6=5.6

2f +2.6=2.1+2.6=2+2.6=4.6

5.6≠ 4.6

Method of substitution can only help her to decide the expresssions are not equivalent, but if she wants to prove the expressions are equivalent, she must prove it for all values of f.

3f+2.6=2f+2.6

3f=2f

3f-2f=0

f=0

This is true only when f=0.

Hence,

The expressions are not equivalent because Ella did not know that you can’t use substitution to test for equivalence.

this what i know

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The lifespans of lions in a particular zoo are normally distributed. The average lion lives 12.512.512, point, 5 years; the stan

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Complete Question

The lifespans of lions in a particular zoo are normally distributed. The average lion lives 12.5 years; the standard deviation is 2.4 years. Use the empirical rule (68-95-99.7\%)(68−95−99.7%) to estimate the probability of a lion living between 5.3 to 10. 1 years.

Answer:

Thehe probability of a lion living between 5.3 to 10. 1 years is 0.1585

Step-by-step explanation:

The empirical rule formula states that:

1) 68% of data falls within 1 standard deviation from the mean - that means between μ - σ and μ + σ.

2) 95% of data falls within 2 standard deviations from the mean - between μ – 2σ and μ + 2σ.

3) 99.7% of data falls within 3 standard deviations from the mean - between μ - 3σ and μ + 3σ.

Mean is given in the question as: 12.5

Standard deviation : 2.4 years

We start by applying the first rule

1) 68% of data falls within 1 standard deviation from the mean - that means between μ - σ and μ + σ.

μ - σ

12.5 -2.4

= 10.1

We apply the second rule

2) 95% of data falls within 2 standard deviations from the mean - between μ – 2σ and μ + 2σ.

μ – 2σ

12.5 - 2 × 2.4

12.5 - 4.8

= 7.7

We apply the third rule

3)99.7% of data falls within 3 standard deviations from the mean - between μ - 3σ and μ + 3σ.

μ - 3σ

= 12.5 - 3(2.4)

= 12.5 - 7.2

= 5.3

From the above calculation , we can see that

5.3 years corresponds to one side of 99.7%

Hence,

100 - 99.7%/2 = 0.3%/2

= 0.15%

And 10.1 years corresponds to one side of 68%

Hence

100 - 68%/2 = 32%/2 = 16%

So,the percentage of a lion living between 5.3 to 10. 1 years is calculated as 16% - 0.15%

= 15.85%

Therefore, the probability of a lion living between 5.3 to 10. 1 years

is converted to decimal =

= 15.85/ 100

= 0.1585

8 0

2 years ago

Type the correct answer in each box. A music company is introducing a new line of acoustic guitars next quarter. These are the c

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Answer:

The company has to produce more than 92 guitars and sell them for making a profit.

Step-by-step explanation:

These are the cost and revenue functions, where x represents the number of guitars to be manufactured and sold: R(x) = 120x, and C(x) = 100x + 1840.

Therefore, the condition for no loss-no gain for manufacturing x number of guitars is

R(x) = C(x)

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⇒ x = 92

Therefore, the company has to produce more than 92 guitars and sell them for making a profit. (Answer)

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2 years ago

Machines A and B always operate independently and at their respective constant rates. When working alone, Machine A can fill a p

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Answer:

The value of x is $\frac{10}{3}$ hours.

Step-by-step explanation:

Machine A = 5 hours

Machine B = x hours

Machine A and B = 2 hours

Using the formula: $\frac{T}{A} + \frac{T}{B} = 1$

where:

T is the time spend by both machine

A is the time spend by machine A

B is the time spend by machine B

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Let multiply the entire problem by the common denominator (5B)

$5x(\frac{2}{5} + \frac{2}{x} = 1)$

2x + 10 = 5x

Collect the like terms

10 = 5x - 2x

10 = 3x

3x = 10

Divide both side by the coefficient of x (3)

$\frac{3x}{3} = \frac{10}{3}$

$x = \frac{10}{3}$ hours.

Therefore, Machine B will fill the same lot in $\frac{10}{3}$ hours.

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2 years ago

Would apreciate if someone helped me..

PtichkaEL [24]

Answer:

a). x = 11

b). m∠DMC = 39°

c). m∠MAD = 66°

d). m∠ADM = 36°

e). m∠ADC = 18°

Step-by-step explanation:

a). In the figure attached,

m∠AMC = 3x + 6

and m∠DMC = 6x - 49

Since "in-center" of a triangle is a points where the bisectors of internal angles meet.

Therefore, MC is the angle bisector of angle AMD.

and m∠AMC ≅ m∠DMC

3x + 6 = 8x - 49

8x - 3x = 49 + 6

5x = 55

x = 11

b). m∠DMC = 8x - 49

= (8 × 11) - 49

= 88 - 49

= 39°

c). m∠MAD = 2(m∠DAC)

= 2(30)°

= 60°

d). Since, m∠AMD + m∠ADM + m∠MAD = 180°

2(39)° + m∠ADM + 66° = 180°

78° + m∠ADM + 66° = 180°

m∠ADM = 180° - 144°

= 36°

e). m∠ADC = $\frac{1}{2}(m\angle ADM)$

= $\frac{1}{2}(36)$

= 18°

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2 years ago

A person died leaving property worth rs.4000.40. His widow get 0.125 of the property and his son got 0.4 of the remainder. What

belka [17]

Answer:

Widow's Share = Rs 500.05

Son's share = Rs 1400.14

Step-by-step explanation:

Property = 4000.40

Widow get share = 0.125

So, Share of Widow = 0.125 * 4000.40

Widow's Share = Rs 500.05

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Son's share = 0.4 * 3500.35

Son's share = Rs 1400.14

6 0

2 years ago