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
Mashcka [7]
3 years ago
8

-2,-7,-12 ,.... is an arithmetic sequence Find the sum of its first 20 terms ?​

Mathematics
1 answer:
nlexa [21]3 years ago
4 0

Given sequence:

-2,-7,-12 ,..

Unknown;

Find the sum of the first 20 terms = ?

Solution:

  The sequence is -2,-7,-12 ,..

To find he sum of n-terms of a sequence, we use the expression below;

     Sₙ  = \frac{n}{2} (2a + (n-1)d)

where n is the number of terms = 20

           a is the first term = -2

            d is the common difference= -7 - (-)2 = -5

Now input the parameters and solve;

       Sₙ  = \frac{20}{2} (2(-2) + (20 - 1) x -5)

      Sₙ = 10(-4 + -5(19))  = 10(-99)  = -990

The sum of the first 20 terms of the sequence is -990

You might be interested in
How do you find the hypotenuse of a triangle?
earnstyle [38]

The hypotenuse is always opposite the right angle and it is always the longest side of the triangle.

Hope this helped ;)

6 0
3 years ago
Read 2 more answers
An insulator is installing fiberglass insulation in exterior walls that total up to​ 1,623 square feet after windows and doors a
ahrayia [7]

Answer:

143 because if you subtract 49 and 28 you get 21 the you divide 21 and 1623

6 0
2 years ago
What is the vertex of the parabola defined by the equation
avanturin [10]

Answer: B. (2,2)

Step-by-step explanation:

The vertex of the parabola in the form (x-h)^2 = 4p(y-k) is (h, k).

7 0
1 year ago
How many solutions does the equation 3x-2x+4=2+x+2 have?
Vikentia [17]
It has only one solution because it is a linear equation
5 0
3 years ago
Read 2 more answers
Can someone please help me? I can't find the h(x) for 0. I also need help with the last question. Please I need it very soon.
Solnce55 [7]

9514 1404 393

Answer:

  see attachments for a table and graph

Step-by-step explanation:

I find it convenient to use a graphing calculator or spreadsheet to do repetitive computations reliably.

__

Your specific question asks for h(0):

  h(0) = -|0 +2| +1 = -2 +1

  h(0) = -1

You may want to check your other table values.

8 0
2 years ago
Other questions:
  • If f(x) = 3x2 + 1 and g(x) = 1 – x, what is the value of (f – g)(
    10·2 answers
  • The formula for the volume of a sphere is v= 4/3 3.14rWhat is the formula solved for r?
    6·1 answer
  • Based on the survey results from 300 selected students in the Burbank School District (BSD), the 98% confidence interval used to
    12·1 answer
  • How many fewer points did the class earn on monday than on Thursday
    5·1 answer
  • 70.4 is what percent of 88?
    6·1 answer
  • What is the slope of the line containing the points (-3,8) and (1,-4)
    7·2 answers
  • Find the angle for this problem
    6·1 answer
  • Pleaseeeee help!!!!!
    8·1 answer
  • In exponential smoothing, the equation involves what type of value that is not part of the moving averages equation?
    8·1 answer
  • Write an equation in the form y = m x + b for the following table:
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!