What are the variables for X and Y

Which expression is equivalent to -1/4( -1/2x - 3/4) -1/2 ( 3/4x + 1/8)

solniwko [45]

Answer:

Step-by-step explanation:

$\frac{-1}{4}(\frac{-1}{2}x-\frac{3}{4})-\frac{1}{2}(\frac{3}{4}x+\frac{1}{8})\\\\=\frac{-1}{4}*\frac{-1}{2}x-\frac{-1}{4}*\frac{3}{4}-\frac{1}{2}*\frac{3}{4}x-\frac{1}{2}*\frac{1}{8}\\\\=\frac{1}{8}x+\frac{3}{16}-\frac{3}{8}x-\frac{1}{16}\\\\=\frac{1}{8}x-\frac{3}{8}x+\frac{3}{16}-\frac{1}{16}\\\\=\frac{(1-3)x}{8}+\frac{3-1}{16}\\\\=\frac{-2}{8}x+\frac{2}{16}\\\\=\frac{-1}{4}x+\frac{1}{4}$

4 0

3 years ago

A pathologist knows that 14.9% of all deaths are attributable to myocardial infarctions (a type of heart disease). (Either you h

garik1379 [7]

Answer:

a) The mean number is 745 and the standard deviation is 25.18.

b) 896 deaths is a significantly high number, which means that there is cause for concern.

Step-by-step explanation:

For each death, there are only two possible outcomes. Either it is attributable to myocardial infarctions, or it is not. The probability of a death being attributable to myocardial infarctions is independent of other deaths. So we use the binomial probability distribution to solve this question.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

$\sqrt{V(X)} = \sqrt{np(1-p)}$

A value X is significantly high is:

$X > E(X) + 2\sqrt{V(X)}$

In this problem:

$p = 0.149, n = 5000$

a. Find the mean and standard deviation for the number of such deaths that will occur in typical region with 5000 deaths.

$E(X) = np = 5000*0.149 = 745$

$\sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{5000*0.149*0.851} = 25.18$

The mean number is 745 and the standard deviation is 25.18.

b. In one region, 5000 death certificates are examined, and it is found that 896 deaths were attributable to myocardial infarction. Is there cause for concern? Why or why not?

Is 896 a significantly high number?

$E(X) + 2\sqrt{V(X)} = 745 + 2*25.18 = 795.36$

895 > 795.36

896 deaths is a significantly high number, which means that there is cause for concern.

6 0

3 years ago

Carrie and dave each rent the aame size moving truck for one day they pay a fee x dollars for the truck and y dollars per mile t

Elina [12.6K]

Answer:

The amount of the fee for the truck is $20 and cost per mile is $1.3.

Step-by-step explanation:

If they pay a fee x dollars for the truck and y dollars per mile they drive.

Carrie drives 150 miles and pays $215.

Her fee= $x for the truck + 150 X y =215

x+150y=215...(I)

Similarly, Dave drives 120 miles and pays $176

His fee =$x for the truck + 120 X y = 176

x+120y=176....(ii)

To determine the values of x and y, we solve Equations I and II simultaneously.

x+150y=215...(I)

x+120y=176....(ii)

Using elimination method (Subtracting equation II from I)

30y=39

y=1.3

Substitute y=1.3 into (I) to get x.

x+150y=215...(I)

x+(150X1.3)=215

x+195=215

x=215-195=20

Since x=20, y=1.3, The amount of the fee for the truck is $20 and cost per mile is $1.3.

5 0

3 years ago

Third-degree, with zeros of -3,-1, and 2, and passes through the point (3,6).

Y_Kistochka [10]

Answer:

Below.

Step-by-step explanation:

In factor form this is:

f(x) = a(x + 3)(x + 1)(x - 2) where a is a number to be found.

As it passes through (3, 6) we have:

6 = a(3 + 3)(3 + 1)(3 - 2)

24a = 6

a = 1/4.

So f(x) = 1/4(x + 3)(x + 1)(x - 2)

In general form this is:

f(x) = 1/4 x^3 + 1/2 x^2 - 5/4 x - 3/2

3 0

2 years ago

Can someone help he understand angles of depression please

Nataly_w [17]

Answer:

The angle of depression of an object becomes the angle between the horizontal and the line of sight from the object to the observer's eye. The angle of depression will be below the observer's eyes.

Step-by-step explanation:

3 0

3 years ago