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> 计算:(1)(45+18)-(8-125)(2)解方程2x2+x-1=0.-数学
计算:(1)(45+18)-(8-125)(2)解方程2x2+x-1=0.-数学
题目简介
计算:(1)(45+18)-(8-125)(2)解方程2x2+x-1=0.-数学
题目详情
计算:
(1)
(
45
+
18
)-(
8
-
125
)
(2)解方程2x
2
+x-1=0.
题型:解答题
难度:中档
来源:不详
答案
(1)原式=3
5
-3
2
-2
2
+5
5
=8
5
-5
2
;
(2)2x2+x-1=0,
分解因式得:(2x-1)(x+1)=0,
2x-1=0,x+1=0,
解得:x1=
class="stub"1
2
,x2=-1.
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题目简介
计算:(1)(45+18)-(8-125)(2)解方程2x2+x-1=0.-数学
题目详情
(1)(
(2)解方程2x2+x-1=0.
答案
=8
(2)2x2+x-1=0,
分解因式得:(2x-1)(x+1)=0,
2x-1=0,x+1=0,
解得:x1=