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3 years ago

An easier question all wrong or unhelpful or no-work answers will be reported.

1 answer:

4 0

Elimination:

3x - 9y = 3
6x - 3y = -24

3x - 9y = 3
18x - 9y = -72
(subtract)
-15x = 75
÷ -15
x = -5

(3 × -5) - 9y = 3
-15 - 9y = 3
+ 15
-9y = 18
÷ -9
y = -2

Substitution:

6x - 3y = -24
+ 3y
6x = -24 + 3y

÷ 6
x = 4 + 0.5y

3(4 + 0.5y) - 9y = 3
12 + 1.5y - 9y = 3
12 - 7.5y = 3
- 12
-7.5y = -9
÷ -7.5
y = 1.2

x = 4 + (0.5 × 1.2)
x = 4 + 0.6
x = 4.6

So this one didn't fail as much, but I got different numbers. If you have to give in values, I'd give in the values from the elimination because I don't trust myself when it comes to the substitution

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The surface area of a cube is 96 square inches. What is the length of an edge of the cube, in inches?

Bezzdna [24]

Answer:

16 inches

Step-by-step explanation:

A cube has 6 sides and to find the surface area you would multiply one side by 6, or add the six sides together. So instead, to find the length of one side, you divide the surface area, 96, by 6 to get 16.

Hope this helps you :)

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3 years ago

Read 2 more answers

What is a matrix for a system of equations that does not have a unique solution?

vlada-n [284]

A system of linear equations can have no solution, a unique solution or infinitely many solutions. A system has no solution if the equations are inconsistent, they are contradictory. for example 2x+3y=10, 2x+3y=12 has no solution. is the rref form of the matrix for this system.

This is in my opinion. Im not sure if it is correct or not but Good luck!

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3 years ago

Yan is climbing down a ladder. Each time he descends four rungs on the ladder, he stops to see how much farther he has to go

anastassius [24]

Question:

Yan is climbing down a ladder. Each time he descends 4 rungs on the ladder, he stopped to see how much farther he has to go. If Yan made eight stops with no extra steps, which expression best shows another way to write the product of the number of ladder rungs that Yan and climbed?

4+4+4+4

8+8+8+8

(-1)(4+4+4+4)

(-8) + (-8) + (-8) + (-8)

Answer:

$Total = (-8) +(-8) +(-8) +(-8)$

Step-by-step explanation:

Given

$Rungs = -4$ --- It is negative because he is climbing down

$Steps = 8$

Required

An expression for the number of rungs climbed

To do this, we simply multiply the number of rungs by the steps taken.

$Total = Rungs * Steps$

$Total = -4 * 8$

This can be rewritten as:

$Total = -8 * 4$

The product, when written as sum is:

$Total = (-8) +(-8) +(-8) +(-8)$

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3 years ago

If x represents the probability of an event happening, then which of the following represents the probability that the event wil

Bad White [126]

If the turn out of an event is to take place or not to take place only then, the sum of the probability of it taking place and not taking place is 1. If we represent the probability of it taking place by x then, the probability of it not taking place is equal to 1 - x.

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3 years ago

2. In how many ways can 3 different novels, 2 different mathematics books and 5 different chemistry books be arranged on a books

insens350 [35]

The number of ways of the books can be arranged are illustrations of permutations.

When the books are arranged in any order, the number of arrangements is 3628800
When the mathematics book must not be together, the number of arrangements is 2903040
When the novels must be together, and the chemistry books must be together, the number of arrangements is 17280
When the mathematics books must be together, and the novels must not be together, the number of arrangements is 302400

The given parameters are:

$\mathbf{Novels = 3}$

$\mathbf{Mathematics = 2}$

$\mathbf{Chemistry = 5}$

(a) The books in any order

First, we calculate the total number of books

$\mathbf{n = Novels + Mathematics + Chemistry}$

$\mathbf{n = 3 + 2 + 5}$

$\mathbf{n = 10}$

The number of arrangement is n!:

So, we have:

$\mathbf{n! = 10!}$

$\mathbf{n! = 3628800}$

(b) The mathematics book, not together

There are 2 mathematics books.

If the mathematics books, must be together

The number of arrangements is:

$\mathbf{Maths\ together = 2 \times 9!}$

Using the complement rule, we have:

$\mathbf{Maths\ not\ together = Total - Maths\ together}$

This gives

$\mathbf{Maths\ not\ together = 3628800 - 2 \times 9!}$

$\mathbf{Maths\ not\ together = 2903040}$

(c) The novels must be together and the chemistry books, together

We have:

$\mathbf{Novels = 3}$

$\mathbf{Chemistry = 5}$

First, arrange the novels in:

$\mathbf{Novels = 3!\ ways}$

Next, arrange the chemistry books in:

$\mathbf{Chemistry = 5!\ ways}$

Now, the 5 chemistry books will be taken as 1; the novels will also be taken as 1.

Literally, the number of books now is:

$\mathbf{n =Mathematics + 1 + 1}$

$\mathbf{n =2 + 1 + 1}$

$\mathbf{n =4}$

So, the number of arrangements is:

$\mathbf{Arrangements = n! \times 3! \times 5!}$

$\mathbf{Arrangements = 4! \times 3! \times 5!}$

$\mathbf{Arrangements = 17280}$

(d) The mathematics must be together and the chemistry books, not together

We have:

$\mathbf{Mathematics = 2}$

$\mathbf{Novels = 3}$

$\mathbf{Chemistry = 5}$

First, arrange the mathematics in:

$\mathbf{Mathematics = 2!}$

Literally, the number of chemistry and mathematics now is:

$\mathbf{n =Chemistry + 1}$

$\mathbf{n =5 + 1}$

$\mathbf{n =6}$

So, the number of arrangements of these books is:

$\mathbf{Arrangements = n! \times 2!}$

$\mathbf{Arrangements = 6! \times 2!}$

Now, there are 7 spaces between the chemistry and mathematics books.

For the 3 novels not to be together, the number of arrangement is:

$\mathbf{Arrangements = ^7P_3}$

So, the total arrangement is:

$\mathbf{Total = 6! \times 2!\times ^7P_3}$

$\mathbf{Total = 6! \times 2!\times 210}$

$\mathbf{Total = 302400}$