If x is an integer, and
x + (x + 1) + … + 2020 + 2021 = 2021
then of course
x + (x + 1) + … + 2020 = 0
and we can write the left side as a sum,
[tex]\displaystyle \sum_{k=0}^n (x+k) = 0[/tex]
with n such that x + n = 2020. (Notice that there are n + 1 terms in the sum.) Then x = 2020 - n, so that
[tex]\displaystyle \sum_{k=0}^n (2020 - n + k) = (2020 - n) \sum_{k=0}^n 1 + \sum_{k=0}^n k= 0[/tex]
Recall that
[tex]\displaystyle \sum_{k=1}^n 1 = 1 + 1 + 1 + \cdots + 1 = n[/tex]
[tex]\displaystyle \sum_{k=1}^n 1 = 1 + 2 + 3 + \cdots + n = \frac{n(n+1)}2[/tex]
Then
[tex]\displaystyle (2020 - n) (n + 1) + \frac{n(n+1)}2= 0[/tex]
Solve for n :
(2020 - n) (n + 1) + n (n + 1) / 2 = 0
4040 + 4039 n - n² = 0
(n - 4040) (n + 1) = 0
⇒ n = 4040 or n = -1
But we are taking the sum of a positive number of terms, so n = 4040.
Then since x + n = 2020, it follows that x = 2020 - 4040 = -2020.
Find the measure of x.
48.99
138
X
x = [?]
Round your answer to the nearest tenth.
Enter
Tan(48.9) = x/138
X = 138 x tan(48.9)
X = 158.2
This question on your unit test is a fill in the blank. Be prepared to type your answer. The graph show how many minutes it takes Ziah to run a certain distance in the city. What is the meaning of the point (4, 6)?
The point (4,6) means it took Ziah 4 minutes to run 6 blocks.
This is because any point is of the form (x,y) where in this case
x = number of minutes
y = number of blocks
So; 1. Find the sum of 64.2 + 3.4 =_____ Find the difference 514 - 1.72=_____
FOR MY BROTHER TWIN'S
" Please answer this today☺️ "
HELP PLEASE
To divide the function f(x) by (x2-4x-12), we find that the quotient is Q(x) and the
remainder is (x+6). If f(-2)=a and f(6)=b, what is the value of b/a?
Answer:
b/a = 3
Step-by-step explanation:
f(x) / (x²-4x-12) = Q(x) + (x+6)/(x²-4x-12)
f(x) = Q(x)*(x²-4x-12) + (x+6)
x= - 2 ... when f(x) is f(-2) x²-4x-12 = 4+8-12 = 0
a = f(-2) = Q(x)*0 + (-2 + 6) = 4
x= 6 ... when f(x) is f(6) x²-4x-12 = 36-24-12 = 0
b = f(6) = Q(x)*0 + (6 + 6) = 12
b/a = 12/4 = 3
A painter uses 15 gallons of interior paint to cover 300 square yards of wall and ceiling space. On a different job, he uses 8 gallons to cover 160 square yards. No paint is left over on either job. How many gallons of paint are needed to cover 1 square yard?
Answer:
.05
Step-by-step explanation:
300/15
20 sqr yrds per gal
1/20
1/20 or .05 Gal per sqr yrd
Please help!! markup and markdown word problems.
1. A boat is marked up 20% on the original price. The original price was $50. What is the sale price of the boat before sales tax?
2. Fred buys a video game disk for $4. There was a discount of 20%. What is the sales price?
3. A painting is on sale at 50% off. The sale price is $320. What was the original price?
Answer:
Step-by-step explanation:
1. A boat is marked up 20% on the original price. The original price was $50. What is the sale price of the boat before sales tax?
$50(1+0.20) = $60
2. Fred buys a video game disk for $4. There was a discount of 20%. What is the sales price?
$4(1-0.2) = $3.20
3. A painting is on sale at 50% off. The sale price is $320. What was the original price?
X*(1-0.5) = $320
X = $320/0.5
X = $640
someone actually help :((( need to finish exam before 12 !!
f(x)=17,000(0.87)x
The value of a certain SUV, in dollars, x years from its model year can be predicted by the exponential function shown in the table.
x| 0| 1| 2| 3| 4| 5|
g(x)| 21,000| 18,690| 16,634.10| 14,804.35| 13,175.87| 11,726.52|
How much more will the SUV be worth than the car 5 years after their model years? Round your answer to the nearest cent.
Using the exponential function, it is found that the SUV is worth $3,253.36 less than the car after 5 years.
The exponential function for the value of the SUV, after x years, is given by:
[tex]f(x) = 17000(0.87)^x[/tex]
Hence, after 5 years, the value is:
[tex]f(5) = 17000(0.87)^5 = 8473.16[/tex]
From the table, after 5 years, the car is worth $11,726.52.
11726.52 - 8473.16 = 3253.36.
The SUV is worth $3,253.36 less than the car after 5 years.
To learn more about exponential functions, you can take a look at https://brainly.com/question/25983065
whats the answer to 3 1/2 divided by 2 1/4
Answer:
1.556
Step-by-step explanation:
Divide
3 and 1 over 23
1
2
÷ 2 and 1 over 42
1
4
= 28 over 18
28
18
Step 1 of 2: Divide, sub-step a: Convert mixed number to improper fraction.
Convert mixed number to improper fraction
3 and 1 over 23
1
2
= ( 3 × 2 ) over 2
3 × 2
2
+ 1 over 2
1
2
= ( 6 + 1 ) over 2
6 + 1
2
= 7 over 2
7
2
Step 1 of 2: Divide, sub-step b: Convert mixed number to improper fraction.
Convert mixed number to improper fraction
2 and 1 over 42
1
4
= ( 2 × 4 ) over 4
2 × 4
4
+ 1 over 4
1
4
= ( 8 + 1 ) over 4
8 + 1
4
= 9 over 4
9
4
Step 1 of 2: Divide, sub-step c: Divide.
Divide
7 over 2
7
2
÷ 9 over 4
9
4
= 7 over 2
7
2
× 4 over 9
4
9
= ( 7 × 4 ) over ( 2 × 9 )
7 × 4
2 × 9
= 28 over 18
28
18
To divide fractions, invert the second one (turn it upside-down), then multiply the numerators and denominators.
Step 1 of 2: Divide.Hide
Step 2 of 2: Simplify.
Simplify
28 over 18
28
18
= 14 over 9
14
9
= 1 and 5 over 91
5
9
Step 2 of 2: Simplify, sub-step a: Reduce fraction to lowest terms.
Reduce fraction to lowest terms
28 over 18
28
18
= ( 28 ÷ 2 ) over ( 18 ÷ 2 )
28 ÷ 2
18 ÷ 2
= 14 over 9
14
9
2 is the greatest common divisor of 28 and 18. Reduce by dividing both numerator and denominator by 2.
Step 2 of 2: Simplify, sub-step b: Convert improper fraction to mixed number.
Convert improper fraction to mixed number
14 over 9
14
9
= 1 and 5 over 91
5
9
14 ÷ 9 = 1 remainder 5
Answer:
1.5555555555556
Step-by-step explanation:
when you divide those numbers, thats your answer
Find the sum of the first 20 terms of the sequence 2, 8, 14, 20, . . ..
Step-by-step explanation:
the rule is obviously to always add 6.
so,
2, 8, 14, 20, 26, 32, 38, 44, 50, 56, 62, 68, 74, 80, 86, 92, 98, 104, 110, 116
Answer:
1180
Step-by-step explanation:
1180 is correct answer
Expand and simplify: (x - 7)(x+7)
Answer:
[tex]x^{2} -49[/tex]
Step-by-step explanation:
Answer:
[tex](x-7)(x+7) =x^2 -7^2 = x^2 -49[/tex]
Step-by-step explanation:
Complete the process of solving the equation.
Fill in the missing term on each line. Simplify any fractions.
9W + 1 = 19
9w =
Subtract 1 from both sides
W =
Divide both sides by 9
Answer:
see explanation
Step-by-step explanation:
9W + 1 = 19 ( subtract 1 from both sides )
9W = 18 ( divide both sides by 9 )
W = 2
help please thank you
Answer:
150*2/3=100
take school size then multiply it by the ratio to get the amount of student who prefer such toothpaste.
Step-by-step explanation:
Can u help me with my homework
How much would you make for the YEAR at $25.02 per hour,
worked 51 hours and do get paid overtime? Round to the nearest
cent.
Answer:
1276.02
Step-by-step explanation:
25.02*51=(25*51)+(.02*51)=1275+1.02=1276.02
What is 29−−√?
What 2 numbers does it fall between when placed on a number line?
Question 5 options:
Between 5 - 5.5
Between 4 - 4.5
Between 4.5 - 5
Between 5.5 - 6
How much pure alcohol must a pharmacist add to 10 cm of a 10% alcohol solution to strengthen it to a 70% solution? ASAP
20 cm³ of pure alcohol is added to 10 cm of a 10% alcohol solution to strengthen it to a 70% solution.
Let x represent the volume of pure alcohol (100%) in cm³ needed to be added. Hence:
x * 100% + 10 cm³ * 10% = 70% * (x + 10 cm³)
x * 1 + 10 * 0.1 = 0.7 * (x + 10)
x + 1 = 0.7x + 7
x - 0.7x = 7 - 1
0.3x = 6
x = 20 cm³
Therefore 20 cm³ of pure alcohol is added to 10 cm of a 10% alcohol solution to strengthen it to a 70% solution.
Find out more on equation at: https://brainly.com/question/13763238
Answer:
20 cm³
Step-by-step explanation:
please help me please
[tex] \frac{76}{90} [/tex]
-_-
I need help please I can’t fail this
Answer:
200
Step-by-step explanation:
200 - 35% = 130
130 + 70 = 200
Which of the following sets is equal to {1, 2, 3, ...)?
{x| xER, x>1}
{x|xER, x> or equal to 1}
{x|xEN, x> or equal to 1}
Answer:
[tex]\{x~ | ~x\in \mathbb{N}, x \geq 1\}[/tex]
Step-by-step explanation:
Does (3, -50) make the equation y = -8x true?
Hey there!
y = -8x
→ -50 = -8(3)
→ -8(3) = -50
→ -8(3) = -24
→ -24 ≠ -50
Yes and no but mainly no because -24 doesn’t equal -50 (the y-intercept)
Answer: NO
Good luck on your assignment and enjoy your day!
~Amphitrite1040:)
What is the constant of proportionality in the following equation?
y = 5x + 0
Answer:
5
Step-by-step explanation:
y is always 5 times greater than x
Number 8 Please!!!!!
Thank You!!!
Answer:
x = 2 + 5i√2 / 6 and x = 2 - 5i√2 / 6
Step-by-step explanation:
If this isn't right, I'm sorry. Also, you can put x = 2 ± 5i√2 /6 to make it shorter and not have two answers. Hope this helps :)
If answer is correct you will be marked as brainliest
What is the discriminant of the polynomial below?
4x^2+4x+1
A. 32
B. -12
C. -4
D. 0
Answer:
Discriminant is [tex] {b}^{2} - 4 \times a \times c [/tex]
[tex]16 - 4 \times 4 \times 1 = 0[/tex]
Is it true that Confidence intervals are always close to their true population values?
Answer:
This means that there is a 95% probability that the confidence interval will contain the true population mean. Thus, P( [sample mean] - margin of error < μ < [sample mean] + margin of error) = 0.95.
Suppose you are the 120th person in line at airport security. In 75 sec, 5 people are able to pass through security. Assuming this rate stays the same, how long (in minutes) will you be waiting in the security line? It takes 15 min to walk from security to the gate for your flight. If the flight stops boarding in 60 min, will you arrive at the gate in time?
Answer:
It takes 30 minutes to get to the front of the line, and 15 minutes to walk, so 45 minutes. 45 is less than 60, so you will make it.
Step-by-step explanation:
To calculate unit rate, 75/5 = 15/1 120*15=1800/60=30 minutes
(divide by 60 to convert to minutes)
Which explanation could be used to verify weather the functions are inverse
Answer:it is the second option
Step-by-step explanation:
neither of the lines are paralell to the y=x
are in the ratio of 3:4. If the first number is decreased by 5, and
the second number is increased by 5, the new ratio will be 2 : 3. What are the two
numbers?
Answer:
the first number is 75 and the second number is 100
- Atriangle is 3 cm wider than it is tall. The area is 14 cm^2. Find the height and the base.
Answer:
7 and 4
Step-by-step explanation:
If you set up a rectangle you get an area of 28 cm^2
4x7=28
the base is 7 cm
the height is 4 cm
what percent of 75cm is 5cm
Answer:
6.67%
Step-by-step explanation:
5 / 75 = 0.066667
(0.066667)(100) = 6.67%
suppose we want to choose 2 colors, without replacement from 3 colors red,bule and green