nth number is 83 hope you understand my answer thanks
Answer: 3n^2 + 8
Step-by-step explanation:
an^2 + bn + c
It is a quadratic sequence
11, 20, 35, 56, 83
+8 +15 +21 +27
+6 +6 +6
a + b + c
4a + 2b + c
9a + 3b + c
4a + 2b + c - a + b + c = 20 - 11
4a + 2b + c - a + b + c = 9
3a + b = 9
9a + 3b + c - 4a + 2b + c = 35 - 20
5a + b = 15
-2a = -6
a = -6/-2
a = 3
Substitute to find the values of b & c
For b
5(3) + b = 15
15 + b = 15
b = 15 - 15
b = 0
For c
9(3) + 3(0) + c = 35
27 + c = 35
c = 35 - 27
c = 8
3n^2 + 0n + 8
3n^2 + 8
