36X X X X 1 2 1 22 2X X X X X X X X( 2 ) 2 36 ...
2 . 36x x x x
1
2
1
2
2
2
x x x x x x x x( 2 ) 2 2 . 36 1
2
1 2
1 2
1
2
2
( ) 2 2 36x x x x x x 1
2
1 2
1 2
0,25 điểm Suy ra : 4 m2
– 2.(-3) + 2.