How do i find this, what’s the formula to find the 20th term and can anyone explain the formula? will award brainliest

Step-by-step explanation:

The first differences of the sequence are ...

Second differences are ...

The second differences are constant, so the sequence can be described by a second-degree polynomial.

We can write and solve three equations for the coefficients of the polynomial. Let's define the polynomial for the sequence as ...

  f(n) = an^2 + bn + c

Then the first three terms of the sequence are ...

Subtracting the first equation from the other two gives ...

  3a +b = 3

  8a +2b = 8

Subtracting the first of these from half the second gives ...

  (4a +b) -(3a +b) = (4) -(3)

  a = 1 . . . . . simplify

Substituting into the first of the 2-term equations, we get ...

  3·1 +b = 3

  b = 0

And substituting the values for a and b into the equation for f(1), we have ...

  1·1 + 0 + c = 2

  c = 1

So, the formula for the sequence is ...

  f(n) = n^2 + 1

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The 20th term is f(20):

  f(20) = 20^2 +1 = 401

Comment on the solution

It looks like this matches the solution of the "worked example" on your problem page.

given that triangle abc is transformed two times to get triangle

a"b"c"

first abc is transformed in to a'b'c' as follows:

the coordinates of a are (1,-1) and transformed into a'(-1,1)

similarly b (4,-2) became b'(-4,2) and

c(7,-2) became c'(-7,2)

i.e. (x,y) becomes (-x,-y)

this is nothing but reflection about a point here origin.

thus first transformation is reflection on the origin.

next is exactly shifting 3 units down

source:

give more details

step-by-step explanation: