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3 years ago

3 pens cost $2.70. What is the cost per pen?

Mathematics

1 answer:

Juliette [100K]3 years ago

6 0

2, 70$ : 3 = 0, 9o $The total cost for each pen
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Help me please. <br> F(x) = 4 - 3x <br> f(10) =

tigry1 [53]

Answer:

f(10) = - 26

Step-by-step explanation:

To evaluate f(10), substitute x = 10 into f(x), that is

f(10) = 4 - 3(10) = 4 - 30 = - 26

8 0

3 years ago

26% of 30 is what number

rewona [7]

Answer:

7.8

Step-by-step explanation:

8 0

3 years ago

What is the solution to the system?

Nutka1998 [239]

Answer:

the (x, y) pair solution to the system is: (-2, -4)

That is x = -2 and y = -4

Step-by-step explanation:

I presume there is a variable y missing in the first equation, and in fact the system looks like:

(1/2) x + (3/2) y = - 7

- 3 x + 2 y = -2

In such case, we proceed to multiply both sides of tye first equation by 6

6 (1/2) x + 6 (3/2) y = - 42

3 x + 9 y = - 42 and we add term by term this equation to the second one, so as to cancel out the term in x:

3 x + 9 y = - 42

- 3 x + 2 y = -2

_____________

11 y = - 44

divide both sides by 11 to isolate y

y = -44 / 11 = -4

Then with the value y = -4, now we replace it in the second equation to solve for x:

- 3 x + 2 y = - 2

- 3 x + 2 (- 4) = -2

- 3 x - 8 = - 2

add 8 to both sides

- 3 x = 6

divide both sides by (-3) to isolate x

x = 6 / (-3) = - 2

Therefore the (x, y) pair solution to the system is: (-2, -4)

That is x = -2 and y = -4

5 0

3 years ago

A public swimming pool that holds 45,000 gallons of water is going to be drained for maintenance at a rate of 100 gallons per mi

neonofarm [45]

Answer: for the first question, after an hour there would be 39,000 gallons left and it would take 450 minutes to drain the pool

Step-by-step explanation:

You multiple the minutes with the rate or which the gallons are being drained and subtract it by the total amount,

Ps can I get the brainliest answer

5 0

3 years ago

Orthogonally diagonalize the matrix, giving an orthogonal matrix P and a diagonal matrix D. To save time, the eigenvalues are

alexgriva [62]

Answer:

$P=\left(\begin{array}{ccc}-\frac{2}{3}&-\frac{2}{3}&\frac{1}{3}\\\frac{1}{\sqrt{5}}&0&\frac{2}{\sqrt{5}}\\-\frac{4}{3\sqrt{5}}&\frac{\sqrt{5}}{3}&\frac{2}{3\sqrt{5}}\end{array}\right)$

Step-by-step explanation:

It is a result that a matrix $A$ is orthogonally diagonalizable if and only if $A$ is a symmetric matrix. According with the data you provided the matrix should be

$A=\left(\begin{array}{ccc}-9&-4&2\\ -4&-9&2\\2&2&-6\\\end{array}\right)$

We know that its eigenvalues are $\lambda_{1}=-14, \lambda_{2}=-5$ , where $\lambda_{2}=-5$ has multiplicity two.

So if we calculate the corresponding eigenspaces for each eigenvalue we have

$E_{\lambda_{1}=-14}=\langle(-2,-2,1)\rangle$ , $E_{\lambda_{2}=-5}=\langle(1,0,2),(-1,1,0)\rangle.$ .

With this in mind we can form the matrices $P, D$ that diagonalizes the matrix $A$ so.

$P=\left(\begin{array}{ccc}-2&-2&1\\1&0&2\\-1&1&0\\\end{array}\right)$

and

$D=\left(\begin{array}{ccc}-14&0&0\\0&-5&0\\0&0&-5\\\end{array}\right)$

Observe that the rows of $P$ are the eigenvectors corresponding to the eigen values.

Now you only need to normalize each row of $P$ dividing by its norm, as a row vector.

The matrix you have to obtain is the matrix shown below

3 0

4 years ago