Question

Which kind of function best models the data in the table? Use differences or ratios.

x y
0 1.7
1 6.8
2 27.2
3 108.8
4 435.2

A.linear
B.quadratic
C.exponential
D.none of the above
I think it is C...?

Answer 1

first difference table

6.8 - 1.7 = 5.1

27.2 - 6.8 = 20.4

108.8 - 27.2 = 81.6

435.2 - 108.8 = 326.4
so not linear

second differences
20.4 - 5.1 = 15.3
81.6 - 20.4 = 61.2
326.4 - 81.6 = 244.8
so not quadratic

try ratios
6.8/1.7 = 4
27.2/6.8 = 4

ah hah ! constant ratio of 4

Answer 2

looks like
y = 1.7(4)^x

Answer 3

sorry about repeat
yes, 1.7 * 4^x

Answer 4

Its c