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> (1)用配方法解方程3x2-x-1=0;(2)解分式方程1x+2+4x2-4+22-x=1.-数学
(1)用配方法解方程3x2-x-1=0;(2)解分式方程1x+2+4x2-4+22-x=1.-数学
题目简介
(1)用配方法解方程3x2-x-1=0;(2)解分式方程1x+2+4x2-4+22-x=1.-数学
题目详情
(1)用配方法解方程3x
2
-x-1=0;
(2)解分式方程
1
x+2
+
4
x
2
-4
+
2
2-x
=1
.
题型:解答题
难度:中档
来源:不详
答案
(1)3x2-x-1=0
x2-
class="stub"1
3
x=
class="stub"1
3
x2-
class="stub"1
3
x+
class="stub"1
36
=
class="stub"1
3
+
class="stub"1
36
(x-
class="stub"1
6
)2=
class="stub"13
36
x-
class="stub"1
6
=
±
13
6
∴x1=
1+
13
6
,x2=
1-
13
6
;
(2)去分母,得(x-2)+4-2(x+2)=x2-4
去括号、移项、合并同类项,得x2+x-2=0
配方得(x+
class="stub"1
2
)2=
class="stub"9
4
∴x+
class="stub"1
2
=±
class="stub"3
2
∴x1=1,x2=-2
当x2=-2时,最简公分母x2-4=0,
∴原方程的根为x=1.
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题目简介
(1)用配方法解方程3x2-x-1=0;(2)解分式方程1x+2+4x2-4+22-x=1.-数学
题目详情
(2)解分式方程
答案
x2-
x2-
(x-
x-
∴x1=
(2)去分母,得(x-2)+4-2(x+2)=x2-4
去括号、移项、合并同类项,得x2+x-2=0
配方得(x+
∴x+
∴x1=1,x2=-2
当x2=-2时,最简公分母x2-4=0,
∴原方程的根为x=1.