题目内容
已知x2-4x+1=0,求代数式(
+
)÷
的值.
x+3 |
x-2 |
1 |
2-x |
x2-4 |
3 |
原式=(
-
)×
=
×
=
=
.
∵x2-4x+1=0,
∴x2-4x=-1,
∴原式=
=1.
x+3 |
x-2 |
1 |
x-2 |
3 |
(x+2)(x-2) |
=
x+2 |
x-2 |
3 |
(x+2)(x-2) |
=
3 |
(x-2)2 |
=
3 |
x2-4x+4 |
∵x2-4x+1=0,
∴x2-4x=-1,
∴原式=
3 |
-1+4 |
练习册系列答案
相关题目