( ) ( )) 5 2 3 – 5 0− + =A X X0,5Đ ( ) ( )X X– 5 – 2 = 0(3,0...
Bài 1
( ) ( )
)
5
2
3 – 5
0
−
+
=
a x
x
0,5đx
x
– 5
– 2 = 0
(3,0− =
=
2 0
2
�
�
đi m)ể�
�
�
− =
�
�
�
=
0,5đ5 0
5
−
−
+
= +
x
x
x
2
1 5
2
b)
13
3
7
( ) ( ) ( )
0,25đ− −
+ =
+
7 2
1 3 5
2
21
13
�
−
+
−
=
+ +
21
14
15
273 6 7
−
=
x
22
286
= −
13
0,25đ c) Đi u ki n: ề ệ x 2;x −2−
=
−
x1
7
6
x 2
2
4
+
−
−
2
− −
+ = −
x1
2
2
6 7
x
x x
x
( ) ( ) ( )
− + − −
= −
2
2
x
x
x
x
x
3
2
2
6 7
=
=
x
x
ktmdk
2
4
2(
)
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