八年级数学应用题急！！！！
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30\u4e2a\u7a7a\u5ea7\u4f4d:
(1)\u6c42\u8be5\u6821\u53c2\u52a0\u6625\u6e38\u7684\u4eba\u6570.
(2)\u5df2\u77e545\u5ea7\u5ba2\u8f66\u7684\u79df\u91d1\u4e3a\u6bcf\u8f86250\u5143,60\u5ea7\u5ba2\u8f66\u7684\u79df\u91d1\u4e3a\u6bcf\u8f86300\u5143,\u8fd9\u6b21\u6625\u6e38\u540c\u65f6\u79df\u7528\u8fd9\u4e24\u79cd\u5ba2\u8f66,\u5176\u4e2d60\u5ea7\u5ba2\u8f66\u6bd445\u5ea7\u5ba2\u8f66\u591a\u79df1\u8f86,\u6240\u4ee5\u79df\u91d1\u6bd4\u5355\u72ec\u79df\u7528\u4e00\u79cd\u5ba2\u8f66\u8981\u7701,\u6309\u8fd9\u79cd\u65b9\u6848\u9700\u7528\u79df\u91d1\u591a\u5c11\u5143?
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x/45=(x+30)/60\uff0b1\u3002\u89e3\u5f97\uff1d270\u3002
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45\uff1d60\uff08x\uff0d1\uff09\uff0d30\u3002\u89e3\u4e4b\uff0c\u5f97\uff1d6\u3002
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250y\uff0b300\uff08y\uff0b1\uff09\uff1c1 500\u3002\u89e3\u4e4b\uff0c\u5f97\uff1c24/11\u3002
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绛旓細1銆佽鐢插伐绋嬮槦姣忓ぉ閾鸿x绫筹紝鍒欎箼宸ョ▼闃熼摵璁緓-20 350/x=250/(x-20)x=70 70-20=50 鎵浠ョ敳70m/澶╋紝涔50m/澶 2銆佸崟鐢叉柦宸ワ細4200/70*3000=180000鍏 鍗曚箼鏂藉伐锛4200/50*2500=210000鍏 涓璧锋柦宸ワ細4200/锛70+50锛*锛3000+2000锛=175000鍏 鎵浠ユ壙鍖呯粰涓ら槦涓璧锋柦宸ュ悎鐞嗐
绛旓細锛1锛夎В锛氳鐢叉瘡鍒嗛挓璺硏涓紝涔欐瘡鍒嗛挓璺硏+5涓 180/x=240/(x+5) 180*(x+5)=240x 180x+900=240x 60x=900 x=15 x+5=15+5=20 绛旓細鐢叉瘡鍒嗛挓璺15涓紝 涔欐瘡鍒嗛挓璺20涓紙2锛夎В:璁剧敳姣忓ぉ鍏卞姞宸涓浂浠讹紝涔欐瘡澶╁叡鍔犲伐35-x涓浂浠.90/x=120/(35-x) 90*(35-x)=120x 315...
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绛旓細鏌愬煄甯傜幇鏈変汉鍙42涓囦汉.璁″垝涓骞村悗鍩庨晣浜哄彛澧炲姞0.8%,鍐滄潙浜轰腑澧炲姞1.1%,杩欐牱鍏ㄥ競浜哄彛寰楀鍔1%,姹傝繖涓煄甯傜幇鏈夊煄闀囦汉鍙ｅ拰鍐滄潙浜哄彛鍒嗗埆鏄灏戜汉?涓変簲涓変竷闉嬪巶涓轰簡浜嗚В鍒濅腑瀛︾敓绌块瀷鐨勯瀷鍙锋儏鍐,瀵圭孩鍗庝腑瀛鍒濅簩(1)鐝殑20鍚嶇敺鐢熸墍绌块瀷鍙风粺璁″涓嬭〃:(1)鍐欏嚭鐢风敓闉嬪彿鏁版嵁鐨勫钩鍧囨暟銆佷腑浣嶆暟銆佷紬鏁;(2)鍦ㄥ钩鍧囨暟銆佷腑浣嶆暟鍜...
绛旓細鐪嬩綔鐢茬嫭浣20澶╋紝鍓╀笅鐨勪箼杩樿鐙綔20+10=30澶┿傛墍浠ヤ箼鐨勬晥鐜囨槸锛1-20/40锛/30=1/60 鎵浠ワ紝涔欏崟鐙共闇瑕1/锛1/60锛=60锛堝ぉ锛変袱闃熷悎浣滈渶瑕1/锛1/40+1/60锛=24锛堝ぉ锛
绛旓細绛旀锛歺=48 y=47 (2) 18x+23y=2303 74x-y=1998 绛旀锛歺=27 y=79 (3) 44x+90y=7796 44x+y=3476 绛旀锛歺=79 y=48 (4) 76x-66y=4082 30x-y=2940 绛旀锛歺=98 y=51 (5) 67x+54y=8546 71x-y=5680 绛旀锛歺=80 y=59 (6) 42x-95y=-1410 21x-y=1575 绛旀锛歺=75 y...
绛旓細浣淐E鈯D浜庣偣E锛屼氦BD浜庣偣F 鈭碘垹A=45掳 鈭碊E=CE 鈭碘垹ADB+鈭燗=鈭燗CE+鈭燗=90掳 鈭粹垹ADB=鈭燗CE 鈭粹柍EFD鈮屸柍ACE 鈭碊F=AC=5 璁綛F=x 鏄撹瘉鈻矪FC鈭解柍BAD 鈭碆F/BC =AB/BD 鈭磝/3=2/(x+5)瑙ｅ緱x=1 鈭碆D =5+1=6 鈭粹柍ABC 鐨勯潰绉=1/2*5*6=15 15-4=11 杩欎釜寮鍙戝尯鐨勫缓绛戝強缁垮寲...
绛旓細5+12+13=30 60梅30=2鍘樼背 涓夎竟闀垮垎鍒负锛5脳2=10鍘樼背 12脳2=24鍘樼背 13脳2=26鍘樼背 10^2+24^2=676 26^2=676 鎵浠ヨ繖鏄釜鐩磋涓夎褰 闈㈢Н涓猴細1/2脳10脳24=120骞虫柟鍘樼背
绛旓細灏忔澃骞冲潎姣忎釜鏈堢殑瀛橀挶鏁版槸灏忎附鐨2鍊,浣嗗皬鏉版瘮灏忎附灏戠敤6涓湀鐨勬椂闂,璇存槑灏忔澃鐢6涓湀,120/6=20,灏忎附涓10鍏.璁惧皬涓芥瘡鏈堝瓨閽盭鍏冿紝灏忔澃灏辨槸瀛2X鍏,灏忎附鐢ㄤ簡120/X鏈,,灏忔澃鐢ㄤ簡120/2X鏈,120/X=120/2X+6 X=10 2X=20
绛旓細瑙ｇ瓟杩囩▼:璁惧伐浣滄婚噺涓篗,鐢叉瘡灏忔椂鍋歺,涔欐瘡灏忔椂鍋歽,鍒欐湁 鏂圭▼1:2x+3y=M/2 鏂圭▼2:M-2x=(M/x+1)y 鍗矼=(2x^2+xy)/(x-y)鏍规嵁鏂圭▼1瑙ｅ嚭y=(M-4x)/6甯﹀叆鏂圭▼2鍚庡彲浠ヨВ鍑簒=M/8(鏂圭▼姹傝В杩囩▼鐪佺暐.)灏唜甯﹀叆鏂圭▼2鍚庡彲浠ヨВ鍑簓=M/12 鍗崇敳姣忓皬鏃跺彲浠ュ仛鎬婚噺鐨1/8,鍗曠嫭闇瑕8灏忔椂瀹屾垚 ...
