A/ X2 4 X 3 X 3
Bài 3 : a/
x
2
4 x 3 x 3
Bài 3: a/x
2
4 x 9 2 x 9
x
3 0
2 9 0
2
x x x
4 3 3
4 9 2 9
0.25
2
3
9
2
5 0
x x
6 18 0( )
x x vn
3 6 0 ( )
0.25
2
2 x 0
0( ) 0;5
x n S
x l S
0.5
0( )
x n
5( )
2( )
x l
ĐỀ 103 ĐỀ 104 b/ 3x2
6x 5 8 2x b/ x2
3x 5 5 2x 5 2 0x8 2x 0
2
3 5 (5 2 )x x x 3x 6x 5 8 2x 0.252
2
x 4 52 x 23 1x 3 0.5 20 3 x 3 0.25 x 1c/x
2
x
2
3 x 5 3 x 7
c/x
2
x
2
x 3 x 9
Đặt t x
2
3 x 5 t 0
Đặt t x
2
x 3 t 0
pt t
2
t 12 0
0.25pt t
2
t 12 0
t n
3( )
0.25 3( )
t l
4( )
3
2
3 5 3
t x x t 3 x
2