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ziro4ka [17]
3 years ago
13

Evaluate 2x2 - 1 when x = 3.

Mathematics
2 answers:
Alla [95]3 years ago
6 0

Answer:11

Step-by-step explanation:2(3)x2-1=11

Charra [1.4K]3 years ago
4 0

Hello!

2.x^2 - 1 = 2.3^2 - 1 = 2.9 - 1 = 18-1 = 17

Good luck!

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sattari [20]
The numbers 55 and 55.
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3 years ago
Assume the general population gets an average of 7 hours of sleep per night. You randomly select 45 college students and survey
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Answer:

a) ii. This is a left-tailed test.

b) -1.59

c) -1.301

d) i. reject null hypothesis

e) Option i) The data supports the claim that college students get less sleep than the general population.

Step-by-step explanation:

We are given the following in the question:  

Population mean, μ = 7 hours

Sample mean, \bar{x} = 6.87 hours

Sample size, n = 45

Alpha, α = 0.10

Sample standard deviation, s =  0.55 hours

First, we design the null and the alternate hypothesis

H_{0}: \mu = 7\text{ hours}\\H_A: \mu < 7\text{ hours}

a) We use one-tailed(left) t test to perform this hypothesis.

b) Formula:

t_{stat} = \displaystyle\frac{\bar{x} - \mu}{\frac{\sigma}{\sqrt{n}} }

Putting all the values, we have

t_{stat} = \displaystyle\frac{6.87 - 7}{\frac{0.55}{\sqrt{45}} } =-1.59

c) Now,

t_{critical} \text{ at 0.10 level of significance, 44 degree of freedom } = -1.301

Since,                    

t_{stat} < t_{critical}

d) We fail to accept the null hypothesis and reject it.

We accept the alternate hypothesis and conclude that  mean number of hours of sleep for all college students is less than 7 hours.

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8 0
3 years ago
The bigger of two numbers is four more
Otrada [13]

Answer:

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y=the larger

The bigger of two numbers is four more than the smaller, then:

y=x+4

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1+2x=y

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y=x+4

y=2x+1

We solve this system by equal values method:

x+4=2x+1

x-2x=1-4

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x=3

We find the value of "y"now:

y=x+4

y=3+4

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the values of x and y are:

x=3

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Step-by-step explanation:

7 0
3 years ago
What is the value of x
Svet_ta [14]

Answer:

32

Step-by-step explanation:

Remark

Every triangle has 180 degrees as the total of its 3 angles.

Equation

x + 98 + 50 = 180

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Combine the like terms on the left

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Wewaii [24]

Answer:

33cm

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add all

numbers..........................

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