某市自来水公司为鼓励用户节约用水，采用按月用水量分段收费办法。某用户应缴水费y（元）与月用水量x（吨 某自来水公司为了鼓励市民节约用水，采用分段收费标准，若某用户...
\u67d0\u5e02\u81ea\u6765\u6c34\u516c\u53f8\u4e3a\u9f13\u52b1\u5c45\u6c11\u8282\u7ea6\u7528\u6c34\uff0c\u91c7\u53d6\u6309\u6708\u7528\u6c34\u91cf\u5206\u6bb5\u6536\u8d39\u529e\u6cd5\uff0c\u82e5\u67d0\u6237\u5c45\u6c11\u5e94\u4ea4\u6c34\u8d39y\uff08\u5143\uff09\u4e0e\u7528\u6c34\u91cfx\uff08\uff081\uff09\u5f530\u2264x\u226415\u65f6\uff0c\u8bbey\u4e0ex\u4e4b\u95f4\u7684\u51fd\u6570\u5173\u7cfb\u5f0f\u4e3ay=k1x\uff0c\u5f53x\uff1e15\u65f6\u8bbey\u4e0ex\u4e4b\u95f4\u7684\u51fd\u6570\u5173\u7cfb\u5f0f\u4e3ay=k2x+b\uff0c\u7531\u51fd\u6570\u56fe\u8c61\uff0c\u5f9727=15k1\uff0c27\uff1d15k2+b39\uff1d20k2+b\uff0c\u89e3\u5f97\uff1ak1=95\uff0ck2\uff1d2.4b \uff1d?9\uff0c\u2234y=1.8x(0\u2264x\u226415)2.4x?9(x\uff1e15)\uff1b\uff082\uff09\u5f53x=10\u65f6\uff0c10\uff1c15\uff0c\u2234y=1.8\u00d710=18\u5143\uff0e\u5f53y=51\u65f6\uff0c51\uff1e27\uff0c51=2.4x-9\uff0c\u89e3\u5f97\uff1ax=25\uff0e\u7b54\uff1a\u67d0\u7528\u6237\u5341\u6708\u4efd\u7528\u6c34\u91cf\u4e3a10\u5428\uff0c\u5219\u5e94\u4ea4\u6c34\u8d3918\u5143\uff1b\u82e5\u8be5\u7528\u6237\u5341\u4e00\u6708\u4efd\u4ea4\u4e8651\u5143\u7684\u6c34\u8d39\uff0c\u5219\u4ed6\u8be5\u6708\u7528\u6c3425\u5428\uff0e
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| （1） 时，y = 1.8 x； x≥15时，y = 2.5 x-10.5 （2）32 = 2.5 x-10.5， x =17， 答：该用户月用水量17吨。 |
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绛旓細鈥滄按鏄敓鍛戒箣婧愨,甯鑷潵姘村叕鍙镐负榧撳姳鐢ㄦ埛鑺傜害鐢姘,鎸変互涓嬭瀹氭敹鍙栨按璐: 鐢ㄦ按閲/鏈 鍗曚綅(鍏/鍚) 涓嶈秴 30 鈥滄按鏄敓鍛戒箣婧愨,甯傝嚜鏉ユ按鍏徃涓洪紦鍔辩敤鎴疯妭绾︾敤姘,鎸変互涓嬭瀹氭敹鍙栨按璐:鐢ㄦ按閲/鏈 鍗曚綅(鍏/鍚)涓嶈秴杩40鍚ㄧ殑閮ㄥ垎 1 瓒呰繃40鍚ㄧ殑閮ㄥ垎 1. 5 鍙:姣忓惃鐢ㄦ按鍔犳敹0. 2鍏冪殑鍩庡競姹℃按澶勭悊璐(1)鏌愮敤鎴1...
绛旓細9(x锛15)锛涳紙2锛夊綋x=10鏃讹紝10锛15锛屸埓y=1.8脳10=18鍏冿紟褰搚=51鏃讹紝51锛27锛51=2.4x-9锛岃В寰楋細x=25锛庣瓟锛氭煇鐢ㄦ埛鍗佹湀浠界敤姘撮噺涓10鍚紝鍒欏簲浜ゆ按璐18鍏冿紱鑻ヨ鐢ㄦ埛鍗佷竴鏈堜唤浜や簡51鍏冪殑姘磋垂锛屽垯浠栬鏈堢敤姘25鍚紟
绛旓細锛1锛 鏃讹紝y = 1.8 x锛 x鈮15鏃讹紝y = 2.5 x-10.5锛2锛32 = 2.5 x-10.5锛寈 =17锛岀瓟锛氳鐢ㄦ埛鏈堢敤姘撮噺17鍚ㄣ
绛旓細纭畾鐢茬敤姘撮噺鐨勮寖鍥达紝鍐嶅缓绔嬩笉绛夊紡姹傚嚭鍏惰В鍗冲彲锛庯紙1)鐢遍鎰忓緱锛20脳2.45锛5 =65.4瑙ｄ箣寰楋紝 =3.28 锛2锛夌敱棰樻剰寰楀綋0鈮 鈮20鏃讹紝 锛涘綋20锛 鈮30鏃讹紝 锛涘綋 锛30鏃讹紝 = 鍗 锛3锛6540脳2%=130.8 鈭20脳2.45=49锛49锛10脳3.28=81.8鑰49锕81.8锕130.8 ...
绛旓細(1) 褰搙鈮10鏃讹紝y=1.5x 褰搙>10鏃讹紝y=1.5*10+锛1.5+0.5锛*锛坸-10锛=15+2(x-10)=2x-5 (2)褰搙=10 鏃讹紝y=15 鐜板湪y=25鍏冿紝璇存槑鐢ㄦ按宸茬粡瓒呰繃10绔嬫柟锛屽嵆x>10 25=2x-5 x=15(绔嬫柟绫)
绛旓細鍋囪鐢ㄦ按閲弜鐨勫崟浣嶆槸鍚 褰0鈮鈮5鏃讹紝y=1.44x锛涜鏄庡綋鐢ㄦ按閲忎笉瓒呰繃5鍚ㄦ椂锛屾瘡鍚ㄦ按搴旂即姘磋垂鏄1.44鍏 褰搙锕5鏃讹紝y=1.8x-1.8 y=1.8(x-5)+5脳1.44 =1.8(x-5)+7.2 =1.8x-9+7.2 =1.8x-1.8 璇存槑锛岀敤姘撮噺瓒呰繃5鍚ㄦ椂锛岃秴杩5鍚ㄩ儴鍒嗘瘡鍚ㄦ按搴旂即姘磋垂1.8鍏冦
绛旓細棰樼洰搴旀槸锛氭按鏄敓鍛戒箣婧愨鏌愬競鑷潵姘村叕鍙镐负榧撳姳浼佷笟鑺傜害鐢姘达紝鎸変互涓嬭瀹氭敹鍙栨按璐癸細濡傛灉姣忔埛姣忔湀鐢ㄦ按涓嶈秴杩40鍚紝閭ｄ箞姣忓惃姘存寜1.8鍏冩敹璐癸紱濡傛灉姣忔埛姣忔湀鐢ㄦ按瓒呰繃40鍚紝閭ｄ箞瓒呰繃閮ㄥ垎鎸夋瘡鍚2.2鍏冩敹璐广傚彟澶栨瘡鍚ㄥ姞鏀0.2鍏冪殑鍩庡競姹℃按澶勭悊璐广鏌愪紒涓涓鏈堜唤鍏变氦姘磋垂224鍏冿紝鍒欎竴鏈堜唤鐢ㄦ按澶氬皯锛熷垯涓鏈堜唤鐢ㄦ按=...
绛旓細x鈮5锛墆=0.9x-0.9锛坸锛5锛夛紙2锛墄鈮5鑷潵姘村叕鍙鐨勬敹璐规爣鍑嗘槸姣忓惃0.72鍏冿紟x锛5鑷潵姘村叕鍙哥殑鏀惰垂鏍囧噯鏄瘡鍚0.90鍏冿紱锛3锛夋病鏈夎秴杩3.6鍚紝鎸0.72鍏冩瘡鍚紝瓒呰繃3.6鍚紝瓒呰繃閮ㄥ垎鎸0.9鍏冩敹璐癸紟鑻鏌鎴峰眳姘戣鏈堢敤姘3.5鍚紝鍒欏簲浜ゆ按璐2.52鍏冿紟鑻ユ煇鎴峰眳姘戣鏈堜氦姘磋垂9鍏冿紝鍒欑敤姘11鍚紟
绛旓細杩欎袱棰樺潎涓哄垎娈佃绠椼傜涓棰橈細锛1锛夊皬浜戝鐢ㄦ按閲11鍚ㄥ湪12鍚ㄤ互鍐咃紝鎵浠ユ寜姣忓惃2.5鍏冭绠楋紝鍒楀紡锛2.5脳11=27.5锛堝厓锛夌瓟锛氬皬浜戝涓婁釜鏈堝簲缂存按璐27.5鍏冦傦紙2锛夊皬鍙鐢ㄦ按閲17鍚ㄨ秴杩12鍚紝瓒呭嚭閮ㄥ垎闇鎸夋瘡鍚3.8鍏冭绠楋紝鍒楀紡锛2.5脳12+锛17-12锛壝3.8 =30+19 =49锛堝厓锛夌瓟锛氬皬鍙涓婁釜...
