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> 先化简、再求值:求代数式x-33x2-6x÷(x+2-5x-2)的值,其中x是一元二次方程x2+3x-2=0的根.-数学
先化简、再求值:求代数式x-33x2-6x÷(x+2-5x-2)的值,其中x是一元二次方程x2+3x-2=0的根.-数学
题目简介
先化简、再求值:求代数式x-33x2-6x÷(x+2-5x-2)的值,其中x是一元二次方程x2+3x-2=0的根.-数学
题目详情
先化简、再求值:求代数式
x-3
3
x
2
-6x
÷(x+2-
5
x-2
)
的值,其中x是一元二次方程x
2
+3x-2=0的根.
题型:解答题
难度:中档
来源:不详
答案
原式=
class="stub"x-3
3x(x-2)
÷(
x
2
-4
x-2
-
class="stub"5
x-2
)
=
class="stub"x-3
3x(x-2)
÷
x
2
-9
x-2
=
class="stub"x-3
3x(x-2)
×
class="stub"x-2
(x+3)(x-3)
=
class="stub"1
3x(x+3)
=
class="stub"1
3
(x
2
+3x)
,
∵x2+3x-2=0,
∴x2+3x=2,
∴原式=
class="stub"1
3×2
=
class="stub"1
6
.
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题目简介
先化简、再求值:求代数式x-33x2-6x÷(x+2-5x-2)的值,其中x是一元二次方程x2+3x-2=0的根.-数学
题目详情
答案
=
=
=
=
∵x2+3x-2=0,
∴x2+3x=2,
∴原式=