Ngày tải lên :
08/11/2013, 19:11
... -1; -2; 2
b. = [
2
2
−
x
-
2
)2(
4
−
x
] : [
)2) (2(
1
+−
xx
+
2
1
−
−
x
]
=
2
)2(
4 42
−
−−
x
x
:
)2) (2(
21
+−
−−
xx
x
=
2
)2(
)4 (2
−
−
x
x
.
)1(
)2) (2(
+−
+−
x
xx
=
)1) (2(
)2) (4 (2
+−
+−−
xx
xx
1
0 ,5
0 , 25
0 , 25
0 , 25
0 , 25
... ( 4x
2
– 4)
= x
2
( x
2
– 1) – 4 ( x
2
– 1)
= ( x
2
– 1)( x
2
– 4)
= ( x – 1)( x + 1)( x – 2) ( x + 2)
0 , 25
0 , 25
0 , 25
0 , 25
0 , 25
0 , 25
0 , 25
0 , 25
4
Vẽ hình đúng ghi GT, KL
a. Tứ giác DEBF ...
)1) (2(
)2) (4 (2
+−
+−−
xx
xx
1
0 ,5
0 , 25
0 , 25
0 , 25
0 , 25
3
a. = ( x
3
– 3x
2
) – ( 4x – 12)
= x
2
( x – 3) – 4( x – 3)
= ( x – 3)( x
2
– 4)
= ( x – 3)( x – 2) ( x+ 2)
b, = ( x
4
– x
2
) – ( 4x
2
– 4)
= x
2
( x
2
–...