SUDOKU

Write a number from 1 to 9 into each empty square in the grid so that every number from 1 to 9 appears exactly once in each horizontal row, each vertical column, and each 3×3 block.
  75      6    
1            98
3      1      5
      3  2      
    6  5  7    
      9          
6      2      7
  1          84
  38      25  
*** Hard