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2 years ago

Solve the system of equations below using elimination.

Mathematics

1 answer:

laiz [17]2 years ago

4 0

Answer:

$y = 4 \\ x = - 2$

Step-by-step explanation:

$y = 4 \\ x = - 2$

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If Anna's test grades are 66, 90, and 99, what is her test average?

marysya [2.9K]

Answer:

90 because it is the mean

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2 years ago

Read 2 more answers

erastovalidia [21]

Answer:

D .

Sorry if i'm wrong.

$x(2 {x}^{2} + 4x - 1 )\\ = 2 {x}^{3} + 4 {x}^{2} - x$

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2 years ago

Halp meer............

klio [65]

Answer:

Step-by-step explanation:

Well, 1/3 is in between 0 and 1. Only D is in between 0 and 1.

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2 years ago

What is the formula for the expected number of successes in a binomial experiment with n trials and probability of success p? C

charle [14.2K]

Answer:

$(D)E[ X ] =np.$

Step-by-step explanation:

Given a binomial experiment with n trials and probability of success p,

$f(x)=\left(\begin{array}{c}n\\k\end{array}\right)p^x(1-p)^{n-x}, 0\leq x\leq n$

$E(X)=\sum_{x=0}^{n}xf(x)= \sum_{x=0}^{n}x\left(\begin{array}{c}n\\k\end{array}\right)p^x(1-p)^{n-x}$

Since each term of the summation is multiplied by x, the value of the term corresponding to x = 0 will be 0. Therefore the expected value becomes:

$E(X)=\sum_{x=1}^{n}x\left(\begin{array}{c}n\\x\end{array}\right)p^x(1-p)^{n-x}$

Now,

$x\left(\begin{array}{c}n\\x\end{array}\right)= \frac{xn!}{x!(n-x)!}=\frac{n!}{(x-)!(n-x)!}=\frac{n(n-1)!}{(x-1)!((n-1)-(x-1))!}=n\left(\begin{array}{c}n-1\\x-1\end{array}\right)$

Substituting,

$E(X)=\sum_{x=1}^{n}n\left(\begin{array}{c}n-1\\x-1\end{array}\right)p^x(1-p)^{n-x}$

Factoring out the n and one p from the above expression:

$E(X)=np\sum_{x=1}^{n}n\left(\begin{array}{c}n-1\\x-1\end{array}\right)p^{x-1}(1-p)^{(n-1)-(x-1)}$

Representing k=x-1 in the above gives us:

$E(X)=np\sum_{k=0}^{n}n\left(\begin{array}{c}n-1\\k\end{array}\right)p^{k}(1-p)^{(n-1)-k}$

This can then be written by the Binomial Formula as:

$E[ X ] = (np) (p +(1 - p))^{n -1 }= np.$

5 0

3 years ago

Abbot Tools is designing a new toolbox. The length of the toolbox will be three times its width, w, and the length of the diagon

Ilia_Sergeevich [38]

The length and width of the toolbox given the diagonal is 45 inches and 15 inches respectively.

<h3>Triangle</h3>

Width of the triangle = w
Length of the triangle = 3w
Diagonal = 30 inches

Hypotenuse ² = opposite ² + adjacent ²

30² = w² + (3w²)

30² = 4w²

900 = 4w²

w² = 900/4

= 225

w = √225

w = 15

Therefore,

Width of the triangle = w

= 15 inches

Length of the triangle = 3w

= 3(15)

= 45 inches

Learn more about triangles:

brainly.com/question/24382052

#SPJ1

5 0

1 year ago