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3 years ago

Im losing brain cells please answer

Mathematics

2 answers:

Irina18 [472]3 years ago

6 0

Answer:

A...i think

Step-by-step explanation:

icang [17]3 years ago

6 0

The answer is D, since her sister is four years older than her.

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Which of the following systems has infinitely many solutions?

stich3 [128]

Answer:

Step-by-step explanation:

4 0

3 years ago

In a class of 666, there are 444 students who are secretly robots.

sveta [45]

Answer:

1/15

Step-by-step explanation:

2/6 for the first one the first the second is 1/5, so 2/6=1/3, so 1/3 x 1/5 = 1/15 your answer is 1/15

3 0

3 years ago

The length of a rectangle is 4 yd less than three times the width, and the area of the rectangle is 55 ya? Find the dimensions o

inysia [295]

Answer:

length = 11 yard

width = 5 yard

Step-by-step explanation:

Area of a rectangle = L W

where A = 55 yard

L = 3W - 4

find: Length

width

solution:

A = L W

55 = (3W - 4) W

55 = 3W² - 4W

3W² - 4W - 55 = 0

use quadratic equation to solve for W:

W = <u> - (-4) ± √(-4)² - 4(3)-55 </u>

2(3)

W = 5, W = -11/3

substitute W=5 to equation L = 3W - 4 to solve for L

L = 3W - 4

L = 3(5) - 4

L = 15 - 4

L = 11

therefore, the dimensions of a rectangle:

length = 11 yard

width = 5 yard

6 0

3 years ago

Let x denote the lifetime of a mcchine component with an exponential distribution. The mean time for the component failure is 25

aliina [53]

Answer:

0.1353 = 13.53% probability that the lifetime exceeds the mean time by more than 1 standard deviations

Step-by-step explanation:

Exponential distribution:

The exponential probability distribution, with mean m, is described by the following equation:

$f(x) = \mu e^{-\mu x}$

In which $\mu = \frac{1}{m}$ is the decay parameter.

The probability that x is lower or equal to a is given by:

$P(X \leq x) = \int\limits^a_0 {f(x)} \, dx$

Which has the following solution:

$P(X \leq x) = 1 - e^{-\mu x}$

The probability of finding a value higher than x is:

$P(X > x) = 1 - P(X \leq x) = 1 - (1 - e^{-\mu x}) = e^{-\mu x}$

The mean time for the component failure is 2500 hours.

This means that $m = \frac{2500}, \mu = \frac{1}{2500} = 0.0004$

What is the probability that the lifetime exceeds the mean time by more than 1 standard deviations?

The standard deviation of the exponential distribution is the same as the mean, so this is P(X > 5000).

$P(X > x) = e^{-0.0004*5000} = 0.1353$

0.1353 = 13.53% probability that the lifetime exceeds the mean time by more than 1 standard deviations

4 0

3 years ago

How many roots does this has?<br>x^2+(2√5x)+2x=-10<br>find Discriminant

Alexxandr [17]

Given:

The equation is

$x^2+(2\sqrt{5})+2x=-10$

To find:

The number of roots and discriminant of the given equation.

Solution:

We have,

$x^2+(2\sqrt{5})x+2x=-10$

The highest degree of given equation is 2. So, the number of roots is also 2.

It can be written as

$x^2+(2\sqrt{5}+2)x+10=0$

Here, $a=1, b=(2\sqrt{5}+2), c=10$ .

Discriminant of the given equation is

$D=b^2-4ac$

$D=(2\sqrt{5}+2)^2-4(1)(10)$

$D=20+8\sqrt{5}+4-40$

$D=8\sqrt{5}-16$

$D\approx 1.89>0$

Since discriminant is $8\sqrt{5}-16\approx 1.89$ , which is greater than 0, therefore, the given equation has two distinct real roots.

3 0

3 years ago