某市为了鼓励市民节约用水，采用分段计费的方法按月计算每户家庭的水费
\u67d0\u5e02\u4e3a\u4e86\u9f13\u52b1\u5e02\u6c11\u8282\u7ea6\u7528\u6c34\uff0c\u91c7\u7528\u5206\u6bb5\u8ba1\u8d39\u7684\u65b9\u6cd5\u6309\u6708\u8ba1\u7b97\u6bcf\u6237\u5bb6\u5ead\u7684\u6c34\u8d39,\u6708\u7528\u6c34\u91cf\u4e0d\u8d85\u8fc720t\u65f6\uff0c\u63092\u5143/t(1).\u5f530\u2264x\u226420\u65f6,y=_2X_ .\u5f53x\uff1e20\u65f6,y=2*20+(X-20)*2.6___.(\u7528\u542bx\u7684\u4ee3\u6570\u5f0f\u8868\u793a);
(2)\u5c0f\u660e\u5bb6\u8fd9\u4e2a\u5b63\u5ea6\u5171\u7528\u6c3430/2+34/2+[40/20+(47.8-40)/2.6]=15+17+(20+3)=55(\u5ea6\uff09
\uff081\uff09\u5f53\u65f60\u2264x\u226420\uff0c\u4e0e\u7684\u51fd\u6570\u8868\u8fbe\u5f0f\u662fy=2x\uff1b
\u5f53\u65f6x\uff1e20\uff0c\u4e0e\u7684\u51fd\u6570\u8868\u8fbe\u5f0f\u662f\uff0c\u5373y=2.6x-12\uff1b
\uff082\uff09\u56e0\u4e3a\u5c0f\u660e\u5bb6\u56db\u3001\u4e94\u6708\u4efd\u7684\u6c34\u8d39\u90fd\u4e0d\u8d85\u8fc740\u5143\uff0c\u516d\u6708\u4efd\u7684\u6c34\u8d39\u8d85\u8fc740\u5143\uff0c\u6240\u4ee5\u628ay\uff1d30\u4ee3\u5165y\uff1d2x\u4e2d\uff0c\u5f97x\uff1d15\uff1b\u628ay\uff1d34\u4ee3\u5165y\uff1d2x\u4e2d\uff0c\u5f97x\uff1d17\uff1b\u628ay\uff1d42.6\u4ee3\u5165y\uff1d2.6x\uff0d12\u4e2d\uff0c\u5f97x\uff1d21\uff0e
\u6240\u4ee515+17+21\uff1d53\uff0e
\u7b54\uff1a\u5c0f\u660e\u5bb6\u8fd9\u4e2a\u5b63\u5ea6\u5171\u7528\u6c3453m2\uff0e
绛旓細浜旀湀浠界殑姘磋垂閮戒笉瓒呰繃40鍏冿紝鍏湀浠界殑姘磋垂瓒呰繃40鍏冿紝 鎵浠ユ妸y=30浠ｅ叆y=2x涓紝寰梮=15锛涙妸y=34浠ｅ叆y=2x涓紝寰梮=17锛 鎶妝=47.8浠ｅ叆y=2.6x锕12涓紝
绛旓細浜旀湀浠界殑姘磋垂閮戒笉瓒呰繃40鍏冿紝鍏湀浠界殑姘磋垂瓒呰繃40鍏冿紝鎵浠ユ妸y=30浠ｅ叆y=2x涓緱锛2x=30锛寈=15锛涙妸y=34浠ｅ叆y=2x涓緱锛2x=34锛寈=17锛涙妸y=42.6浠ｅ叆y=2.6x锕12涓緱锛
绛旓細(1).褰0鈮鈮20鏃,y=_2X_ .褰搙锛20鏃,y=2*20+(X-20)*2.6___.(鐢ㄥ惈x鐨勪唬鏁板紡琛ㄧず);(2)灏忔槑瀹惰繖涓搴﹀叡鐢ㄦ按30/2+34/2+[40/20+(47.8-40)/2.6]=15+17+(20+3)=55(搴︼級
绛旓細绛旓細锛1锛変笉瓒5鍚ㄦ椂锛屾瘡鍚ㄦ按鏀惰垂10/5=2鍏冿紱瓒呰繃5鍚ㄦ椂锛岃秴杩囬儴鍒嗙殑姣忓惃姘存敹璐癸紙20.5-10锛/(8-5)=3.5鍏 锛2锛夎嫢鏌愭埛灞呮皯鏌愭湀鐢ㄦ按3.5鍚紝涓嶈冻5鍚紝搴斾氦姘磋垂涓2*3.5=7鍏 鑻ヨ鐢ㄦ埛鏌愭湀浜ゆ按璐17鍏冿紝鍥犱负鐢5鍚ㄦ按涓10鍏冿紝瓒呰繃5鍚ㄦ寜3.5/鍚ㄨ绠楋紝锛17-10锛/3.5=2 璇ョ敤鎴峰綋鏈堢敤姘...
绛旓細(1)y=1.1x+0.1(0鈮鈮10)y=2(x-10)+1.1脳10+0.1=2x-8.9(x锛10)(2)鍥犱负骞冲潎姘磋垂涓烘瘡鍚1.6鍏冿紝鎵浠ヤ娇鐢▂=2x-8.9(x锛10)锛屽緱 (2x-8.9)梅x=1.6 瑙ｅ緱x=22.25
绛旓細瑙ｏ細褰搙=16鏃讹紝搴斾氦姘磋垂16*2=32鍏 褰搙=25鏃讹紝搴斾氦姘磋垂20*2+锛25-20锛*2.6=53鍏
绛旓細2x x<=20 40+2.6(x-20) x>20 鏍规嵁棰樻剰锛氭湰瀛ｅ害姘磋垂锛15*2+17*2+40+2.6*锛21-20锛=30+34+40+2.6=106.6
绛旓細1. 褰0鈮鈮20鏃,y=2X 褰搙锛20鏃,y=40+2.6(X-20)2. 15+ 17+ 21= 53
绛旓細锛1锛夊綋 0鈮鈮20鏃讹紝y=2x 褰 x>20鏃讹紝y=2.6*锛坸-20锛+2*20 鍗 y=2.6x-12 锛2锛墄=20 绔嬫柟鏃讹紝y=40鍏冿紝鎵浠ヤ粠琛ㄤ腑鍙互鐪嬪嚭鍙湁6鏈堜唤鐢ㄦ按瓒呰繃浜20绔嬫柟 4鏈堜唤鐢ㄦ按 30=2x锛寈=15绔嬫柟 5鏈堜唤鐢ㄦ按 34=2x锛寈=17绔嬫柟 6鏈堜唤鐢ㄦ按 42.6=2.6x-50锛寈=21 杩欎釜瀛ｅ害鍏辩敤姘 15+17+21...
绛旓細锛1锛夊綋0鈮鈮20 y涓巟鐨勫嚱鏁拌〃杈惧紡涓y=2x x锛20鏃 y涓巟鐨勫嚱鏁拌〃杈惧紡涓簓=2.6(x-20) + 20*2=2.6x--12 (2)褰0鈮鈮20 0<=y<=40 2x4=30 x4=15 2*x5 =34 x5 =17 42.6>40 2.6x6-12=42.6=21 灏忔槑瀹惰繖涓搴﹀叡鐢ㄦ按x4+x5+x6=53绔嬫柟绫 ...
