Here, sum of last column = 0 + 11 + 7 + 12

Solving for last row,

x + 2 + 1 + 12 = 30

∴ x = 15

Solving for first column,

x + 8 + 4 + 15 = 30

∴ x = 3

Solving for first row,

3 + 14 + x + 0 =30

∴ x = 13

Solving for second row,

8 + x + 6 + 11 = 30

∴ x = 5

Solving for second column,

14 + 5 + x + 2 = 30

∴ x = 9

Solving for third column,

13 + 6 + x + 1 = 30

∴ x = 10