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3 years ago

Choose the value of x that makes the open sentence true 40-x^2 < 2x+15.

Mathematics

2 answers:

S_A_V [24]3 years ago

6 0

I believe the answer is B, but I'm not 100% sure. :)

Anastasy [175]3 years ago

4 0

the answer is 5.

hope it helps

You might be interested in

(13) The temperature on a cold winter day is 2 degrees below zero. In the night, the temperature drops an additional 14 degrees.

EastWind [94]

Well, in the first one, 2 degrees below zero is -2 degrees, and then it says that it dropped 14 degrees, which means it dropped -14 degrees, so to know the total amount it dropped you would just have to add -2 plus -14 which is -16 degrees, so your answer for the first question would be the last answer, -16 degrees.

For the second question, just know that whenever a negative number is BY ITSELF in parentheses, that means it is used like a positive number in the equation. So (-12) automatically becomes 12. Now, since the problem is asking for a SUM, (the answer to an ADDITION problem; when you add instead of subtract), you would turn that minus symbol to a plus symbol, and add normally to get your final answer; 30 + 12 = 42. To check if this is correct, just type in <span>30 – (–12) to a calculator and you'll get the same answer! :D
Hope this helps! :3</span>

5 0

3 years ago

A clinical trial tests a method designed to increase the probability of conceiving a girl. In the study 335335 babies were born

strojnjashka [21]

Answer:

The 99% confidence interval estimate of the percentage of girls born is (74.37%, 85.63%).

Usually, 50% of the babies are girls. This confidence interval gives values considerably higher than that, so the method to increase the probability of conceiving a girl appears to be very effective.

Step-by-step explanation:

Confidence Interval for the proportion:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

For this problem, we have that:

$n = 335, \pi = \frac{268}{335} = 0.8$

99% confidence level

So $\alpha = 0.01$ , z is the value of Z that has a pvalue of $1 - \frac{0.01}{2} = 0.995$ , so $Z = 2.575$ .

The lower limit of this interval is:

$\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.8 - 2.575\sqrt{\frac{0.8*0.2}{335}} = 0.7437$

The upper limit of this interval is:

$\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.8 + 2.575\sqrt{\frac{0.8*0.2}{335}} = 0.8563$

For the percentage:

Multiplying the proportions by 100.

The 99% confidence interval estimate of the percentage of girls born is (74.37%, 85.63%).

Usually, 50% of the babies are girls. This confidence interval gives values considerably higher than that, so the method to increase the probability of conceiving a girl appears to be very effective.

7 0

3 years ago

Amelia is training for a triathlon. She swims 3/5 mile. Then she runs about 6 times farther than she swims. About how far does A

il63 [147K]

Answer:

so if amelia swims 3/5 then runs 6 times that fraction you put 6/1 and you times 3times 6 and 5 times 1 sp that equals 18/5

Step-by-step explanation:

6 0

3 years ago

Help me with this please

natita [175]

Could you maybe rotate the picture so we can see it better?