what do you have to do the same to each of the following number in the left columns to acheive the answers?

Question

2 , 3 = 0
3 , 4 = 4
4 , 5 = 12
5 , 6 = 24

Answer 1

Minus 2 from each number, multipy them together, then multiply by 2.

Answer 2

look at the function x ----> 2(x^2 + x). f(0)=0, f(1)= 4, f(2) = 12 and f(3) = 24. So G(n,n+1)= 2( n-2)x(n-1). In other words, you substract 2 to each, multiply and then multiply the result by 2.