开关脱扣器:(45x+30)(33x+15)-(45x+30)(33x+160=0

来源:百度文库 编辑:高考问答 时间:2024/04/29 08:19:24
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(45x+30)(33x+15)-(45x+30)(33x+160)=0
(45x+30)[(33x+15)-(33x+160)]=0
(45x+30)(33x+15-33x-160)=0
(45x+30)(-145)=0
-6525x-4350=0
-6525x=4350
x=-2/3

(45x+30)(33x+15)-(45x+30)(33x+160)=0变形得
(45x+30)(33x+15)-(45x+30)[(33x+30)+130]=0
(45x+30)(33x+15)-(45x+30)(33x+30)-(45x+30)*130=0
(45x+30)*130=0
x=-2/3

(45x+30)(33x+15)=(45x+30)(33x+16)
45x*33x+45x*15+30*33x+30*15=45x*33x+45*16+30*33x+30*16
去掉两边相同部分得:
45x*15+30*15=45x*16+30*16
675x+450=720x+480
移项得:
720x-675x=450-480
45x=-30
x=-2/3

(45x+30)(33x+15)-(45x+30)(33x+160=0
(45x+30)[33x+15-(33x+160)]=0
-145(45x+30)=0
45x+30=0
x=-30/45=-2/3