一艘轮船从重庆到上海用5天，回来用了7天，问一只木筏从重庆到上海用几天用一元一次方程式解啊？
\u7269\u7406\uff1a\u4e00\u8f6e\u8239\u4ece\u91cd\u5e86\u5230\u4e0a\u6d775\u5929\uff0c\u800c\u4ece\u4e0a\u6d77\u5230\u91cd\u5e867\u5929\uff0c\u6709\u4e00\u6728\u724c\u4ece\u91cd\u5e86\u987a\u6d41\u6f02\u5230\u4e0a\u6d77\u8981\u591a\u5c11\u5929\uff1f\uff08\u7528\u7269\u7406\u77e5\u8bc6\u89e35=s/\uff08v+v\u6c34\uff09 7=s/\uff08v-v\u6c34\uff09 v=6s/35 v\u6c34=s/35
t=s/v\u6c34=35\u5929
\u8bbe\u8239\u901fa\u5343\u7c73\u6bcf\u65f6\uff0c\u6c34\u901fX\u5343\u7c73\u6bcf\u65f6
5(a+x)=7(a-x)
a=6x
\u5e26\u5165\u5f9735\u5929
N天
绛旓細鐢35澶╁晩锛岃鍑洪潤姘撮熷害鍜杞埞閫熷害锛屽氨鍙互姹傚緱浜
绛旓細璁惧畾鑸归熶负v1锛屾按娴侀熷害涓簐2锛屾湁5(v1+v2)=7(v1锛峷2)锛 =>v1=v2锛屼唬鍏ユ柟绋嬪彲寰楅渶瑕35澶┿
绛旓細鑸归熷害 V1 姘存祦閫烿2 涓婃捣鍒伴噸搴嗚矾绋 S : S/(V1+V2)=5 S/(V1-V2)=7 鍙互寰楀嚭 V1=6V2锛孲=35V2 褰撹埞閫熷害V1鍙樻垚2琚悗锛孷1=12V2锛屼粠涓婃捣鍒伴噸搴鏃堕棿涓 T=S/(12V2-V2)=35/11=3.2澶
绛旓細璁捐埞鏈韩鐨勯熷害涓篨锛屾按娴侀熷害涓篩锛浠庨噸搴嗗埌涓婃捣椤烘祦鑰屼笅锛岄熷害绛変簬鑸归熷姞姘撮熶负X+Y锛屾诲叡闇浜斿ぉ锛姣忓ぉ琛屽叏绋嬬殑1/5锛屼粠涓婃捣鍒伴噸搴嗛嗘祦鑰屼笂锛岄熷害绛変簬鑸归熷噺姘撮熶负X-Y锛屾诲叡闇7澶╋紝姣忓ぉ琛屽叏绋嬬殑1/7锛屾牴鎹鎰忓垪鍑烘柟绋嬶細X+Y锛1/5 X-Y锛1/7 瑙ｅ緱锛歑锛6/35锛孻锛1/35 鎵浠ワ紝姘寸殑閫熷害鏄瘡澶...
绛旓細12鏄煎
绛旓細宸茬煡锛歵1=5澶╋紝t2=7澶╋紝璁捐埞鐨勮埅閫熶负akm/澶╋紝姘寸殑娴侀熶负bkm/澶╋紝姹傦細姘寸殑娴侀浠庨噸搴嗗埌涓婃捣鐨勬椂闂磘3锛岃В锛歴=(a+b)*t1=(a-b)*t2锛屽嵆锛5(a+b)=7(a-b)锛屸斺斻媋=6b锛屸斺斻媠=(a+b)*t1=35b锛屸斺斻媡3=s/b=35(澶)锛岀瓟锛氱暐銆
绛旓細棣栧厛锛屽亣璁捐埞閫熶竴瀹氫负X/澶╋紝姘存祦涓瀹氫负A/澶╋紝鍏ㄧ▼闀夸负S锛涳紙X+A锛*5T=锛圶-A锛*7T =S X=6A S=(6A+A)*5T=锛6A-A锛*7T=35T*A 鎵浠ヨ35澶╀簡鈥︹閲嶅簡浜旀枟绫虫杩庝綘鍟婏紒锛侊紒
绛旓細5=s/锛坴+v姘达級 7=s/锛坴-v姘达級 v=6s/35 v姘=s/35 t=s/v姘=35澶
绛旓細宸茬煡锛杞埞閫熷害鏄疺锛孉涓嶣璺濈涓篠锛涗粠A鍒癇椤烘祦锛屾椂闂磘1鏄7澶╋紝閫嗘祦鏃堕棿t2=5澶╋紝姹傛按娴侀熷害浠嶢鍒癇鏃堕棿锛氳В锛氭按娴侀熷害vo S/锛圴+vo锛=5 S/锛圴-vo锛=7 鑱旂珛瑙ｅ緱V=6vo S=35vo t=S/vo=35澶
绛旓細鐢茶溅璧扮殑璺▼涓:5m/4=50鍗冪背.鍙堝洜涓:鐢蹭箼鐨勯熷害涔嬫瘮鏄5锛4,鏃剁浉閬,鍒橝銆丅涓ゅ湴鐩歌窛涓:40+50=90鍗冪背.2.涓鑹樿疆鑸逛粠閲嶅簡鍒颁笂娴瑕5澶,璇存槑椤烘祦.鍙浠庝笂娴鍒伴噸搴嗚7澶,璇存槑閫嗘祦.璁,椤烘祦鏃舵按鐨勯熷害涓篤,鍥犱负(V鑸+V)*5=(V鑸-V)*7,V鑸=6V,鑰,(V鑸+V)*5=1,(6V+V)*5=1,V=1/35,閭...
