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
Misha Larkins [42]
2 years ago
12

. Find the sum of the first 20 terms of the arithmetic sequence 27, 22, 17, ....

Mathematics
1 answer:
valkas [14]2 years ago
8 0

Answer:

Step-by-step explanation:

a = 27

n = 20

d = -5

L20 = 27 + (n - 1)*d

L20 = 27 + (20-1)*_5

L20 = 27 + 19*-5

L20 = -68

Sum = (a + L)*n/2

Sum = (27 - 68)*20/2

Sum = -41 * 10

Sum = - 410

You might be interested in
Find the formula for df^-1/dx.<br><br> f(x)=(7-x)^3
klio [65]
Here is the equation to solve the problem above:

f(x) = (7-x)^3
y = (7-x)^3

switch y and x
 x = (7 - y)^3
 
third root of x = 7 - y
-y = 3rootx - 7
 
so:<span><span>f′(x)=3^<span>√x</span>−7</span></span>
7 0
2 years ago
Which correlation should be used to measure the relationship between gender and grade point average for a group of college stude
Alecsey [184]
I believe the correct answer would be A. The best correlation to use to measure the relationship between gender and grade point average for a group of college students would be the point-biserial correlation. It is coefficient that is used when a variable is dichotomous or that the variable is part of a whole set. It is used in measuring the direction of the correlation that is present between a dichotomous variable and a continuous variable. From the  question, the dichotomous variable would be the grade point average for a group of college students while the other variable is the continuous one. 
4 0
3 years ago
Read 2 more answers
Work out the value 3x10^-5 x 40,000,000 give you answer in standard form​
Olenka [21]

<u>★ Solution:</u>

➣ {\sf{3\:x\:10^{-5}\:x\:4\:x\:10^7

➣ {\sf{(3\:x\:4)\:x\:(10^{-5+(-7)})

➣ {\sf{12\:x\:10^2

➣ {\sf{1.2\:x\:10^3

3 0
2 years ago
Please help. Don’t understand this math problem!
oksian1 [2.3K]

Answer:

  { 4 }

Step-by-step explanation:

First you need to solve the equation. Then you need to write the solutions as a set.

__

I like to use a graphing calculator to solve equations involving roots. That helps avoid extraneous solutions. Here, the graph of the left side intersects the graph of the right side at x=4. There is exactly one solution, so the solution set is ...

  { 4 }

__

Solving this algebraically, you would isolate the radical, then "undo" it by squaring both sides of the equation. Then solve the resulting quadratic. That will have 2 solutions, only one of which will work in the original equation.

  √(5x +16) -2 = 3x -8 . . . . given

  √(5x +16) = 3x -6 . . . . . .  add 2

  5x +16 = (3x -6)^2 . . . . .  square both sides

  5x +16 = 9x^2 -36x +36 . . . . expand the square

  9x^2 -41x +20 = 0 . . . . . . subtract (5x+16) to put into standard form

Factors of 9·20 = 180 that have a sum of 41 are 5 and 36, so we can rewrite this equation as ...

  9x^2 -36x -5x +20 = 0

  9x(x -4) -5(x -4) = 0 . . . . . . factor by pairs

  (9x -5)(x -4) = 0

The values of x that make this equation true are the values that make the factors be zero: 5/9 and 4. Trying these in the equation, we find ...

  √(5(5/9) +16) -2 = 13/3 -2 = 2 1/3 . . . . value of the left side for x = 5/9

  3(5/9) -8 = -6 1/3 . . . . . . value of the right side for x=5/9; not the same

  x = 5/9 is NOT A SOLUTION

__

  √(5(4)+16) -2 = √36 -2 = 4 . . . . value of the left side for x = 4

  3(4) -8 = 12 -8 = 4 . . . . . . value of the right side for x=4. These are the same, so ...

  x = 4 is a solution

The set of solutions is then ...

  { 4 } . . . . . solution set

5 0
2 years ago
Find the wronskian of the set {1 - x, 1 + x, 1 - 3x}.​
bija089 [108]

Answer:

Correct option is

A

−415

1(x+1x−1)=3x

⇒x+1x−1=3⇒x+1x−1=9

x−1=9x+9

−8x=10⇒x=4−5

f(3)=3(4−5)=4−15

8 0
2 years ago
Read 2 more answers
Other questions:
  • Factor the expression by taking out the GCF. 3x - 9x3
    11·1 answer
  • What property is illustrated by this question? 0.2x + 1.3 + 3.9x + 9.75 A.
    15·1 answer
  • Select the following numbers that cannot represent the area of a polygon.
    10·2 answers
  • 1/2 (3x + 5) = 7 <br> anyone can someone explain this problem to me so I can understand it better.
    6·1 answer
  • 11. The surface area of a triangular prism is 78 square inches. What is
    12·1 answer
  • [IMAGE] i need help with 1-4 pls help ASAP
    9·1 answer
  • Math please help will give brainiest.
    10·2 answers
  • Select all of the numbers that are irrational.
    5·2 answers
  • 1. Q1) Which number is missing from this prime factor<br>tree?<br>​
    15·1 answer
  • The mean per capita consumption of milk per year is 144 liters with a variance of 484. If a sample of 183 people is randomly sel
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!