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2 years ago

If y=29,find x y=(x+2)(x-2) Please show working

Mathematics

2 answers:

Ainat [17]2 years ago

6 0

Answer:

x=±sqrt (33)

Step-by-step explanation:

y=(x+2)(x-2)

29=x^2-4. x^2=33, x=±sqrt (33)

Nina [5.8K]2 years ago

4 0

Answer:

$\sqrt{33}$

Step-by-step explanation:

y = (x+2) (x-2)

y = $x^{2}$ +2x -2x-4

y = $x^{2}$ - 4

29 = $x^{2}$ - 4

29 + 4 = $x^{2}$ -4 + 4

33 = $x^{2}$

$\sqrt{33}$ = x

Hope this is clear and you can understand it. :)

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The population of the world was 7.1 billion in 2013, and the observed relative growth rate was 1.1% per year. A) Estimate how lo

VLD [36.1K]

Answer:

A) 63.36 years.

B) 100.42 years.

Step-by-step explanation:

We have been given that the population of the world was 7.1 billion in 2013, and the observed relative growth rate was 1.1% per year.

A) Since we know that population increases exponentially, therefore we will use our given information to form an exponential model for population increase and then we will solve for the time by which our population will be double.

$P(t)=7.1(1.011)^{t}$

$7.1 \times 2=7.1(1.011)^{t}$

$\frac{7.1 \times 2}{7.1} =(1.011)^{t}$

$2 =(1.011)^{t}$

Now let us solve for t using logarithm.

$ln(2) =ln (1.011)^{t}$

$ln(2) =t \cdot ln(1.011)$

$0.6931471805599453 =t \cdot 0.0109399400383344$

$t=\frac{0.6931471805599453}{0.0109399400383344}$

$t=63.3593217267282743049\approx 63.36$

Therefore, it will take 63.36 years the population to be double.

B) Now we will find the number of years it will take the population to be triple of its size.

$7.1 \times 3=7.1(1.011)^{t}$

$\frac{7.1 \times 3}{7.1} =(1.011)^{t}$

$3 =(1.011)^{t}$

Now let us solve for t using logarithm.

$ln(3) =ln (1.011)^{t}$

$ln(3) =t \cdot ln(1.011)$

$1.0986122886681097 =t \cdot 0.0109399400383344$

$t=\frac{1.0986122886681097}{0.0109399400383344}$

$t=100.4221490079915311298\approx 100.42$

Therefore, it will take 100.42 years the population to triple of its size.

6 0

3 years ago

1. A sample consists of 75 TV sets purchased several years ago. The replacement times of those TV sets have a mean of 8.2 years.

Greeley [361]

Answer:

8.2+/-0.25

= ( 7.95, 8.45) years

the 95% confidence interval (a,b) = (7.95, 8.45) years

Step-by-step explanation:

Confidence interval can be defined as a range of values so defined that there is a specified probability that the value of a parameter lies within it.

The confidence interval of a statistical data can be written as.

x+/-zr/√n

Given that;

Mean x = 8.2 years

Standard deviation r = 1.1 years

Number of samples n = 75

Confidence interval = 95%

z value(at 95% confidence) = 1.96

Substituting the values we have;

8.2+/-1.96(1.1/√75)

8.2+/-1.96(0.127017059221)

8.2+/-0.248953436074

8.2+/-0.25

= ( 7.95, 8.45)

Therefore the 95% confidence interval (a,b) = (7.95, 8.45) years

3 0

2 years ago

I wanted to walk one mile each day in the morning I walked 4/10 if a mile and in the evening I walked 2/5 of a mile what was the

Vitek1552 [10]

4/10 is also equal to 2/5 and 2+2 equals four therefore you would get 4/5 as your final answer

7 0

3 years ago

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There are 12 marbles in a box. 8 are purple, and 4 are green. What is the probability of picking a purple marble and then a gree

Bad White [126]

Answer: 8/33

Step-by-step explanation:

So the probability of picking a purple marble is 8/12, after that there are 11 marbles left in the box

Now the probability of picking a green marble without placing the first marble back is 4/11

So the probability of doing both is 8/12 x 4/11 = 8/33

8 0

2 years ago

Solve y = -7(-13)<br><br> I'm giving 30 points!

VARVARA [1.3K]

y = -7(-13)

=> y = -7 × (-13)

= y = 91

4 0

3 years ago

Read 2 more answers