1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
aliya0001 [1]
3 years ago
15

The sum of the first n terms of an arithmetic sequence is n/2(4n + 20).

Mathematics
1 answer:
lesantik [10]3 years ago
8 0

Answer:

(a).

S_{n} =  \frac{n}{2} (4n + 20) \\  \\S _{n - 1} =  \frac{(n - 1)}{2} (4n - 4 + 20) \\  \\ S _{n - 1} =  \frac{(n - 1)}{2} (4n + 16) \\  \\S _{n - 1} = \frac{(n - 1)(4n + 16)}{2}  \\   \\  { \boxed{S _{n - 1} =  {2 {n}^{2} + 6n - 8}}} \\

(b).

from general equation:

S _{n - 1} =  \frac{(n - 1)}{2} (4n + 16)

first term is 4n

common difference:

16 =  \{(n - 1) - 1 \}d \\ 16 = (n - 2)d \\ d =  \frac{16}{n - 2}

You might be interested in
Plz help yall ;-; I need this by tonight​
attashe74 [19]
Answer

x^154
54b^20

step by step
3 0
3 years ago
Read 2 more answers
Nadia needs one cup of ice cream for every student in her class for their year-end party. the ice cream is only sold in pints. i
mylen [45]

Answer:

12 pints

Step-by-step explanation:

There are 24 students & each one gets 1 cup, so you will need 24 cups total.  There are 2 cups in a pint.  You divided the 24 cups you need by 2 cups in a pint to get the answer of 12 pints.

You can double check:  12 pints converted to cups (2 cups in a pint) is 12 x2 = 24 cups

7 0
2 years ago
Find the LCM of 4 and 9<br><br> A. 9<br> B. 35<br> C. 72<br> D. none of the above
Vitek1552 [10]
B is the answer becuase it’s 35 and that should be correct
7 0
3 years ago
Read 2 more answers
(a) use the pythagorean theorem to determine the length of the unknown side of the triangle, (b) determine the perimeter of the
ki77a [65]

Answer/Step-by-step explanation:

a. Unknown side, b, using the Pythagorean theorem is solved as shown below.

b^2 = c^2 - a^2

b^2 = 45^2 - 27^2

b^2 = 1,296

b = \sqrt{1,296}

b = 36

Unknown side, b, = 36 km

b. Perimeter of the triangle = sum of all the sides of the ∆ = 36 + 45 + 27

perimeter = 108 km

c. Area of triangle = ½*base*height

where,

Base = 36 km

Height = 27 km

Area = \frac{1}{2}*36*27

Area = 18*27

Area = 486 km^2

7 0
3 years ago
PLEASE HELP ASAP!!
Alexeev081 [22]

Answer:

729

Step-by-step explanation:

9x9x9 = 81 x 9

3 0
3 years ago
Read 2 more answers
Other questions:
  • PLEASE HELP ASAP!!!!!!!!!!!
    7·1 answer
  • Given the definitions of f(x) and g(x) below, find the value of (f og)(2).
    9·1 answer
  • 4 times a number is 32 less than the square of that number. Find the negative solution.
    7·1 answer
  • Cookies are on sale! Today each cookie costs \$0.75$0.75dollar sign, 0, point, 75 less than the normal price. Right now if you b
    5·2 answers
  • Factor this polynomial completely.<br> 12x2+x-6
    6·2 answers
  • Which expression is equivalent to -28 x 2 + 35 x ?
    14·1 answer
  • Whats the radius and center of (x+4)^2+(y-2)^2=9
    12·1 answer
  • Help in 5-14 plz I need this in the worst way
    12·1 answer
  • Flying against the wind, an airplane travels 3200 kilometers in 5 hours. Flying with the wind, the same plane travels 6300 kilom
    6·1 answer
  • Find the surface area of the cylinder and round to the nearest tenth. (Use the π button on your calculator)
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!