Replace ? by a number?

Question

Answer 1

Ans is 72.
The given numbers are
2*1^2=2
2*2^2=8
2*3^2=18
2*4^2=32
2*5^2=50
2*7^2=98
2*8^2=128
2*9^2=162
Acc to this the missing will be 2*6^2=72.