一元一次方程的应用,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,解：,（1）某数的5倍加上3等于某数的7倍减去5；,（3）某数的一半加上4，比某数的3倍小21；,根据下列条件列出方程，然后求出某数,（2）某数的3倍减去9等于某数的1/3加上6；,（2）、（3）两题请同学们自己解。,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,例1,如图,天平的两个盘内分别盛有51g、45g盐，问应该从盘A内拿出多少盐到盘B内，才能使两者所盛盐的质量相等？,分析,应从盘A内拿出盐x g ，,列表如下,盘A,盘B,A,B,A,B,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,解：,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,引例,学校团委组织65名团员为学校建花坛搬砖.初一同学每人搬6块,其他年级同学每人搬8块,总共搬了400块.问初一同学有多少人参加了搬砖?,分析,设:初一同学有 人参加了搬砖,列表如下,初一学生,其他年级学生,总数,参加人数,每人搬砖数,共搬砖数,65,400,6,8,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,解：,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,例2,学校团委组织65名新团员为学校建花坛搬砖.女同学每人每次搬6块,男同学每人每次搬8块,每人各搬了4次,共搬了1800块.问这些新团员中有多少名男同学?,分析,设:新团员中有 名男同学,列表如下,男同学,女同学,总数,参加人数,每人共搬砖数,共搬砖数,65,1800,84,64,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,解：,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,练习(课本第11页)第1题,1.学校田径队的小刚在400米跑测试时,先以6米秒的速度跑完了大部分路程,最后以8米秒的速度冲刺到达终点,成绩为1分零5秒,问小刚在冲刺阶段花了多少时间?,400,6,8,65,解:设小刚在冲刺阶段花了 秒时间,根据题意,则,=,400,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,解:小刚在冲刺阶段花了 秒时间,根据题意,则,=,400,答:小刚在冲刺阶段花了 5 秒时间.,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,习题(课本第14页)第4、5题,做一做,4.足球的表面是由一些呈多边形的黑、白皮块缝而成的,共计有32块,已知黑色皮块比白色皮块数的一半多2,问两种皮块各有多少?,解1:设黑色皮块有 块,则白色皮块有 块 ,根据题意,则,(黑色),(白色),解这个方程,得,答:黑色皮块有 12 块,则白色皮块有20 块.,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,习题(课本第14页)第4、5题,做一做,4.足球的表面是由一些呈多边形的黑、白皮块缝而成的,共计有32块,已知黑色皮块比白色皮块数的一半多2,问两种皮块各有多少?,解2:设白色皮块有 块,则黑色皮块有 块 ,根据题意,则,(黑色),(白色),解这个方程,得,答:黑色皮块有 12 块,则白色皮块有20 块.,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,习题(课本第14页)第4、5题,做一做,4.足球的表面是由一些呈多边形的黑、白皮块缝而成的,共计有32块,已知黑色皮块比白色皮块数的一半多2,问两种皮块各有多少?,解3:设白色皮块有 块,则黑色皮块有 块 ,根据题意,则,(黑色),(白色),解这个方程,得,答:黑色皮块有 12 块,则白色皮块有20 块.,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,习题(课本第14页)第4、5题,5.小莉和同学在“五一”假期去森林公园玩,在溪流边的码头租了一艘小艇,逆流而上,划行速度约4千米时.到B地后沿原路返回,速度增加了50,回到A码头比去时少花了20分种.求A、B两地之间的路程.,4,4(1+ 50),即6,解:设A、B两地之间的路程为 千米,据题意得,-,Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.,