4,9,x,37 is a quadratic sequence (a)show that x=20 (b)determine the nth term of the sequence thanks in advance

Answer 1

quadratic sequences will have linear 1st differences and constant 2nd differences.

The 1st differences here are 5,x-9,37-x
The 2nd differences are x-14,46-2x

If x=20, that makes the 1sts: 5,11,17
and the 2nds 6,6

which is consistent.

I expect you can determine the nth term all right...

Answer 2

4du