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
kolezko [41]
2 years ago
15

The first five terms of a quadratic sequence are 3, 12, 25, 42, 63.

Mathematics
1 answer:
skad [1K]2 years ago
7 0

Since we know the sequence is quadratic, we expect the n-th term to have the general form

x_n = an^2 + bn + c

Plug in the first 3 known values of the sequence to form a system of equations.

x_1 = 3 = a + b + c

x_2 = 12 = 4a + 2b + c

x_3 = 25 = 9a + 3b + c

Eliminating c gives

(4a + 2b + c) - (a + b + c) = 12 - 3 \implies 3a + b = 9

(9a + 3b + c) - (a + b + c) = 25 - 3 \implies 8a + 2b = 22 \implies 4a + b = 11

Eliminating b gives

(4a + b) - (3a + b) = 11 - 9 \implies a = 2

Solving for b,c, we get

4a + b = 11 \implies b = 11-4\cdot2 = 3

a+b+c=3 \implies c=3-2-3 = -2

So, the n-th term of the sequence is

x_n = \boxed{2n^2 + 3n - 2}

You might be interested in
Which of the following is the correct equation for the distance formula for the points (x1, y1) and (x2,y2)?
svp [43]

Answer:

  A. D=sqrt( (x2-x1)^2+(y2-y1)^2 )

Step-by-step explanation:

The distance between two points is the root of the sum of the squares of the differences in their corresponding coordinates. The equation of choice A is the usual formulation.

__

<em>Comment on answer choices</em>

Because the square of a number is the same as the square of its opposite, the formula in choice D is also correct.

4 0
3 years ago
Two pounds of grapes cost $6.<br> Using this rate, how much would 1 pound of grapes cost?
Leni [432]
This would cost 3 dollars
6 0
3 years ago
Read 2 more answers
The perimeter of the parallelogram is 102 feet. Find m. Write your answer as a decimal or mixed number. The length is 3m and the
Ann [662]

m is 48 because since they said perimeter you would have to add 3 twice and then subtract is with 102 which is 96 the divide 96 by 2 and you would get 48.

3 0
3 years ago
Concrete can be purchased by the cubic yard. How much will it cost to pour a circular slab 18 ft in diameter by 3 in. for a pati
Brums [2.3K]
280 dollars
Glad I could help
3 0
3 years ago
Read 2 more answers
What could make it fair game
Elden [556K]

what could make it fair game? well in order to make it fair game you would have to change the 5 and or 0 on the board so it wouldn't give you $5 automatically and $0 automatically

8 0
3 years ago
Other questions:
  • Segment lm is the midsegment of trapezoid abcd. ab = 58, and dc = 98. what is lm?
    14·1 answer
  • don't know how to do this kind of math anymore so if someone could me it would be really great 2.54 x .12000 =
    7·1 answer
  • Which statement best describes the graph of this polynomial function f(x)=x^4+x^3-2x^2
    7·1 answer
  • I'm marking answers as brainliest ----- One of the vertices for this linear programming problem is __________. ----- (1,2) (3.5,
    13·1 answer
  • (18x^5+6x^4-12x^3)÷6x^2
    15·1 answer
  • Write a division problem that has a two digit quotient that is greater than 40 but less than 50.
    7·2 answers
  • What’s the slope-intercept form of y + 3 = 4(x - 5),
    12·2 answers
  • Simplify the expression 8xy + 6.3h + 7xy - xy - 2h
    12·1 answer
  • Write the following expression in standard form by expanding and collecting like
    10·1 answer
  • Which of the following choices is equivalent to -9x &gt; -27?
    11·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!