题目列表(包括答案和解析)
61.
解:原式
······························································· 2分
·················································· 2分
原式
60. 解:![]()
![]()
. ………………………4分
(其中通分1分,除法变乘法1分,分子分母分解因式1分,化简1分)
在-3 < p < 3中的整数p是-2,-1,0,1,2, ……………………………………………………5分
根据题意,这里p仅能取-1,此时原式 =
.…………………………………………………6分
(若取p = -2,0,1,2,代入求值,本步骤不得分;直接代-1计算正确给1分)
59. 解:原式=![]()
=
………………2分
=x-4 ………………3分
当
时, 原式=
………………4分
58. 解:原式=
=![]()
=
.
当
,
时,
原式=![]()
57. 解:原式
··········································································· 4分
························································································································· 6分
当
时,原式
.································································································· 7分
56. ![]()
![]()
·············································································································· 4分
.······················································································································ 6分
当
时,
![]()
![]()
.··············································································· 8分
55.
(2)原式=![]()
=
=![]()
54. 解法一:设乙同学的速度为
米/秒,则甲同学的速度为
米/秒,
根据题意,得
,
解得
.
经检验,
是方程的解,且符合题意.
甲同学所用的时间为:
(秒),
乙同学所用的时间为:
(秒).
,
乙同学获胜.
解法二:设甲同学所用的时间为
秒,乙同学所用的时间为
秒,
根据题意,得![]()
解得
经检验,
,
是方程组的解,且符合题意.
,
乙同学获胜.
53. 解: (以下给出一种方案,其他方案略)
=
=![]()
52. 解:设第一天捐款x人,则第二天捐款x+50人,由题意列方程
=
.
化简得,4x+200=5x. 解得 x =200.
检验:当x =200时,x(x+50)≠0,
∴ x =200是原方程的解.
两天捐款人数x+(x+50)=450.
人均捐款
=24.
答:两天共参加捐款的有450人;人均捐款24元
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