here are the first five terms of a quadratic sequence (1 8, 21, 40, 65). the nth term of this sequence can be written in the form (an2 + bn). where a and b are integers. work out the value of a and the value of b

a=3 and b=-2

Step-by-step explanation:

We are given that five  terms of a quadratic sequence are

1 8, 21, 40, 65.

The nth term of this sequence

=

We have to find the value of a and b where a and b are integers.

For n=1

  ......(1)

For n=2

  .....(2)

Subtract equation (1) from (2) we get

Using the value of a=3 in equation (1)

Hence, the value of

a=3 and b=-2

the 4th choice is the correct one

step-by-step explanation: