题目内容
(1)先化简,再求值:x
-
+
(x=
);
(2)解方程:y2+2y-1=0.
|
4x |
9x |
1 |
2 |
(2)解方程:y2+2y-1=0.
(1)原式=
-2
+3
=2
,
当x=
时,
2
=2
=
.
(2)y2+2y-1=0
y2+2y=1
y2+2y+1=1+1
(y+1)2=2
y+1=±
y+1=
,y+1=-
∴y1=
-1,y2=-
-1.
x |
x |
x |
=2
x |
当x=
1 |
2 |
2
x |
|
2 |
(2)y2+2y-1=0
y2+2y=1
y2+2y+1=1+1
(y+1)2=2
y+1=±
2 |
y+1=
2 |
2 |
∴y1=
2 |
2 |
练习册系列答案
相关题目