If 2 3 = 9; 5 4 = 26; and 6 2 = 13 then 7 4 = ??

Question

If

2    3 = 9
5    4 = 26
6    2 = 13

Then

7    4 = ??

Answer 1

Answer is 15.

Solution:

2x3 = 6+3 = 9

5x4 = 20+6 = 26

6-2 = 4+9 = 13

7-4 = 3+12 = 15

Comments

2*3=6+3=9
5*4=20+6=26
6*2=12+1=13
7*4=28+2=30

Answer 2

If we give values of x=0,1,2 corresponding to y=9,26,13 the series follows the curve y=9+32x-15x^2. In that case for the next value of x=3, y comes =30