Is this right? plz answer only if you know!

Did I get the right answer?

BigorU [14]

Answer:

No

Step-by-step explanation:

There needs to be one dot on 3, one dot on 4, two dots on 5, and two dots on 6.

4 0

3 years ago

Find the sum of the first 20 terms of the arithmetic sequence 4, -4, -12, -20

Vsevolod [243]

Answer:

The sum of the first 20 terms is -1440.

Step-by-step explanation:

We want to find the sum of the first 20 terms of the arithmetic sequence:

4, -4, -12, -20...

The sum of an arithmetic sequence is given by:

$\displaystyle S=\frac{k}{2}(a+x_k)$

Where k is the number of terms, a is the initial term, and x_k is the last term.

Since we want to find the sum of the first 20 terms, k = 20.

Our initial term a is 4.

Our last term is also the 20th term as we want the sum of the first 20 terms.

To find the 20th term, we can write an explicit formula for our sequence. The explicit formula for an arithmetic sequence is given by:

$x_n=a+d(n-1)$

Where a is the initial term, d is the common difference, and n is the nth term.

Our initial term is 4. From the sequence, we can see that our common difference is -8 since each subsequent term is eight less than the previous term. Therefore:

$x_n=4-8(n-1)$

Then the last or 20th term is:

$x_{20}=4-8(20-1)=4-8(19)=-148$

Therefore, the sum of the first 20 terms are:

$\displaystyle\begin{aligned} S_{20}&=\frac{(20)}{2}\left((4)+(-148))\\&=10(-144) \\&= -1440\end{aligned}$

5 0

3 years ago

Read 2 more answers

JUST ANSWER PLEASE!!! QUICK

jeka57 [31]

Answer:

Options 1 and 3

Step-by-step explanation:

We should know that, the system of linear equations can be treated as matrices, i.e: we can modify or make any operations provide that we must apply the same operation for all terms of each equation.

Given: the solution for the following system is (2,9)

Px + Qy = R ⇒(1)

Tx + Uy = V ⇒(2)

We will check which system of equation has the same solution.

System A) Px + Qy = R

(P+T)x + (Q+U)y = R+V ⇒(3)

So, By summing (1) and (2) we will get the equation (3)

So, system A has the same solution (2,9)

System B) Px + Qy = R

(P+2T)x + (Q+2U)y = R-2V ⇒(4)

By multiplying equation (2) by 2 and add with equation (1), we will get:

(P+2T)x + (Q+2U)y = R+2V

Which is not the same as equation (4)

So, system B has not the same solution (2,9)

System C) (T-P)x + (U-Q)y = V-R ⇒(5)

Tx + Uy = V

By multiplying equation (1) by -1 and add with equation (2), we will get the equation (5)

So, system C has the same solution of (2,9)

System D) (T-P)x + (Q+U)y = V-R ⇒(6)

Tx + Uy = V

We cannot get equation (6) by the same operation over equation (1)

Note the coefficient of x and y⇒ (T-P) and (Q+U)

They must be (T+P) and (Q+U) OR (T-P) and (Q-U)

So, system D has not the same solution of (2,9)

System E) (5T-P)x + (5U-Q)y = V-5R ⇒ (6)

Tx + Uy = V

By subtract equation (1) from 5 times equation (2), we will get:

(5T-P)x + (5U-Q)y = 5V-R

Which is not the same as equation (6)

So, system E has not the same solution (2,9)

As a conclusion, the systems which have the same solution are:

Options 1 and 3

5 0

3 years ago

Khan Acad

alexandr402 [8]

Answer:

7.222 (repeating)

Step-by-step explanation:

8 + 10 + 8 + 5 + 4 + 7 + 5 + 10 + 8 = 65

1 2 3 4 5 6 7 8 9

65 / 9 = 7.222 (repeating)

6 0

3 years ago

A large farm has 75 acres of wheat and 62.5 acres of corn. The farm crew can harvest the the wheat from 12 acres and the corn fr

Leviafan [203]

In a Farm, there are:
=> 75 acres of wheat
=> 62.5 acres of corn
In each day, the farm crew can harvest:
=> 12 acres of wheat
=> 10 acres of corn
Find how many days can the farm crew harvest all of the plants,
=> 75 / 12
=> 6.25, thus the farm crew will take 6.25 days to be able to harvest acres of wheat
=> 62.5 / 10
=> 6.25, thus the farm crew will take 6.25 days also to harvest acres of corn.

4 0

4 years ago