What is the answer to -4 + 7 = __

I need help finding the answer to this question on edge.

Aliun [14]

Answer:

6

Step-by-step explanation:

We need to evaluate :-

$\rm\implies \displaystyle\rm\sum^4_n (-1)^n (3n + 2 )$

Here the $\Sigma$ is the sum operator . And here we need to find the sum from n = 1 to n = 4 . We can write it as ,

$\rm\implies (-1)^1 ( 3*1 +2) + (-1)^2 ( 3*2+2) + (-1)^3(3*3+2) + (-1)^4(3*4+2)$

Now we know that for odd powers of -1 , we get -1 and for even powers we get 1 . Therefore ,

$\rm\implies -1 ( 3 + 2 ) + 1 (6+2)+-1(9+2)+1(12+2)$

Now add the terms inside the brackets and then multiply it with the number outside the bracket . We will get ,

$\rm\implies -1 * 5 + 1 * 8 + -1*11 + 1*14 \\\\\rm\implies -5 + 8 - 11 + 14 \\\\\rm\implies\boxed{\quad 6 \quad}$

Hence the required answer is 6.

6 0

2 years ago

Sneha is inspecting the average cleanliness of the rooms in a hotel. There are 10 floors in the hotel, each with 20 rooms. From

blondinia [14]

Answer: Stratified sampling

Step-by-step explanation:

Stratified sampling is a particular kind of random sampling technique.

Here , the researcher splits the entire population into distinct groups known as strata.

Then he draw a sample by taking participants from each strata and continue his work on sample.

As per given ,

Researcher = Sneha

Strata = Each floor

Since from each floor she randomly selects 2 rooms and inspects them and then takes the average of these scores.

Therefore , Sneha used the Stratified sampling technique.

5 0

3 years ago

Factor the expression x2 – 9x + 14

Anna [14]

X² - 9x + 14
x² - 2x - 7x + 14
x (x - 2) -7 (x - 2)
x - 7 =0 OR x - 2 = 0
x = 7 OR x = 2

In short, Your Roots would be 2 & 7

Hope this helps!

7 0

3 years ago

Read 2 more answers

Claire wants to start a stamp collection. She spends $15 on an album to hold her stamps and $1.25 for each stamp. If she has $40

enyata [817]

Answer:

20

Step-by-step explanation:

40 - 15 = 25

25/1.25=20

7 0

3 years ago

Katy's favorite rides at the amusement park are the roller coasters and water slide. The wait time for the roller coaster is 25

ioda

Answer:

She went on the slide 8 times and on the roller coaster 4 times

Step-by-step explanation:

We convert each statements to a mathematical equation.

Firstly, let's represent the number of times she went on the coaster with R and the number of times on the slide with S. We know quite well she went on 12 rides. Hence the summation of both number of times yield 12.

Mathematically, R + S = 12. ........(i)

Now we also know her total wait time was 3hours. Since an hour equals 60 minutes, her total wait time would equal 180 minutes.

To get a mathematical representation for the wait time, we multiply the number of roller coaster rides by 25 and that of the slides by 10.

Mathematically, 25R + 10S = 180 .......(ii)

Here we now have two equations that we can solve simultaneously.

From equation 1 we can say R = 12 - S. We can then substitute this into equation 2 to yield the following:

25(12 - s) + 10s = 180

300 - 25s + 10s = 180

300 - 15s = 180

15s = 300 - 180

15s = 120

S = 120/15

S = 8

S = 8 , and R = 12 - S = 12 - 8 = 4

7 0

3 years ago

What is the answer to -4 + 7 = ___