evaluate the following expression using the values given: find 3x − y − 3z if x = −2, y = 1, and z = −2. (1 point) −13 −1 1 13

Formulate the situation as a system of two linear equations in two variables. Be sure to state clearly the meaning of your x- an

slega [8]

Answer:

1) There were 33 $4,000 investors and 27 $8,000 investors.

2) The solution in x = 4, y = 9.

3) There were 24 nickels and 56 dimes.

Step-by-step explanation:

1) A lawyer has found 60 investors for a limited partnership to purchase an inner-city apartment building, with each contributing either $4,000 or $8,000. If the partnership raised $348,000, then how many investors contributed $4,000 and how many contributed $8,000?

I am going to say that:

x is the number of investors that contributed 4,000.

y is the number of investors that contributed 8,000.

Building the system:

There are 60 investors. So:

$x + y = 60$

In all, the partnership raised $348,000. So:

$4000x + 8000y = 348000$

I am going to simplify by 4000. So:

$x + 2y = 87$

Solving the system:

The elimination method is a method in which we can transform the system such that one variable can be canceled by addition. So:

$1)x + y = 60$

$2)x + 2y = 87$

I am going to multiply 1) by -1. So we have

$1)-x - y = -60$

$2)x + 2y = 87$

By addition, the x are going to cancel each other

$-x + x - y + 2y = -60 + 87$

$y = 27$

For x:

$x + y = 60$

$x = 60-y = 60-27 = 33$

There were 33 $4,000 investors and 27 $8,000 investors.

2) Solve the system by row-reducing the corresponding augmented matrix.

$2x + y = 17$

$x + y = 13$

This system has the following augmented matrix:

$\left[\begin{array}{ccc}2&1&17\\1&1&13\end{array}\right]$

To help the row reducing, i am going to swap the first with the second line:

$L1 L2$

So we have:

$\left[\begin{array}{ccc}1&1&13\\2&1&17\end{array}\right]$

Now, reducing the first column.

$L2 = L2 - 2L1$

So we have:

$\left[\begin{array}{ccc}1&1&13\\0&-1&-9\end{array}\right]$

Now we do:

$L2 = -L2$

And the matrix is:

$\left[\begin{array}{ccc}1&1&13\\0&1&9\end{array}\right]$

Now to reduce the second column, we do:

$L1 = L1 - L2$

$\left[\begin{array}{ccc}1&0&4\\0&1&9\end{array}\right]$ .

So the solution is:

x = 4, y = 9.

3) A jar contains 80 nickels and dimes worth $6.80. How many of each kind of coin are in the jar?

I am going to say that x is the number of nickels and y is the number of dimes.

Each nickel is worth 5 cents and each dime is worth 10 cents.

Building the system:

There are 80 coins in all:

$x + y = 80$

They are worth $6.80. So:

$0.05x + 0.10y = 6.80$

Solving the system:

$1)x + y = 80$

$2)0.05x + 0.10y = 6.80$

I am going to divide 1) by -10, so we can cancel y. So:

$1)-0.10x - 0.10y = -8$

$2)0.05x + 0.10y = 6.80$

Adding:

$-0.10x + 0.05x - 0.10y + 0.10y = -8 + 6.80$

$-0.05x = -1.2$ *(-100)

$5x = 120$

$x = \frac{120}{5}$

$x = 24$

Also

$x + y = 80$

$y = 80-x = 80-24 = 56$

There were 24 nickels and 56 dimes.

8 0

3 years ago

In kite ABCD, mZBAE = 28º and mZBCE = 58°. Find mZABE. B E А С D mLABE =

Digiron [165]

Answer:

m∠ABE = 62°

Step-by-step explanation:

Since, the given quadrilateral is a kite, diagonals will intersect at 90°.

Therefore, m∠AEB = m∠CEB = 90°

m∠BAE = 28° [Given]

m∠BCE = 58° [Given]

From ΔABE,

m∠BAE + m∠BEA + m∠ABE = 180°

28° + 90° + m∠ABE = 180°

m∠ABE = 180° - 118°

= 62°

Therefore, measure of angle ABE = 62°.

3 0

3 years ago

What fraction plus 7/8 = 1

Bess [88]

Answer:

1/8

Step-by-step explanation:

yes

6 0

3 years ago

How do you do 5x10+11? Please I am d u m b

jasenka [17]

5 x 10 is 50 then 50 + 11 is 61 so I think it would be 61 ;)

4 0

2 years ago

Read 2 more answers

Will give brainly if correct (hs gemotry)

Brums [2.3K]

Scarlet is leaning a 12 foot ladder. When you lean a 12 foot ladder, it is s slanted so we will make 12 our slanted side or hypotenuse. It makes a 80 degree angle after contact with the ground so it will be on the lowest angle on the right. We are asked to find the vertical side or how high up the ground is. We are asked to a angle that is opposite of the given angle which is x .. And we are also given the hypotenuse. We are going to use sin using our SOHCAHTOA

$\sin(theta) = \frac{opposite}{hypotunese}$

Where there is our given angle.

Let plug it in

$\sin(80) = \frac{x}{12}$

Multiply 12 by both sides and we get

$\sin(80) \times 12 = x$

Which about 11.8 if rounded to nearest tenth or 11.82 if rounded to nearest hundredth.

IF ROUNDED TO NEAREST TENTH, 11.8

IF ROUNDED TO NEAREST HUNDRETH, 11.82

5 0

3 years ago