请教几道数学题目！
\u95ee\u51e0\u9053\u6570\u5b66\u98981.x+2.6=3.8
x=3.8-2.6
x=1.2
2.23.2-x=8
x=23.2-8
x=15.2
3.5x=1.25
x=1.25/5
x=0.25
4.3x+12=60
3x=60-12
3x=48
x=48/3
x=16
5.30+x=45.2
x=45.2-30
x=15.2
6.10-3\u5206\u4e4b1x=5\u5206\u4e4b1
3fenzhi1x=10-5\u5206\u4e4b\u4e00
\u4e09\u5206\u4e4b\u4e00x=9\u53c85\u5206\u4e4b\u4e00
x=5\u5206\u4e4b138
7.3x+x=3.6
4x=3.6
x=3.6/4
x=0.9
1\u3002\u4e00\u4e2a\u6570\u76845\u500d\u518d\u52a0\u4e0a5\u6b63\u597d\u662f100\u8fd9\u4e2a\u6570\u662f\u591a\u5c11\uff1f\uff08\u65b9\u7a0b\u89e3\uff09
\u89e3\uff1a\u8bbe\u8fd9\u4e2a\u6570\u662fx
5x+5=100
5x=100-5
x=95\u00f75
x=19
2\u3002\u4e00\u4e2a\u6570\u76848\u500d\u4e0e\u5b834\u5206\u4e4b1\u7684\u548c\u662f66\uff0c\u8fd9\u4e2a\u6570\u662f\u591a\u5c11\uff1f\uff08\u65b9\u7a0b\u89e3\uff09
\u89e3\uff1a\u8bbe\u8fd9\u4e2a\u6570\u662fx
8x+1/4x=66
x=66\u00f78.25
x=8
3\u3002\u7532\u4e59\u4e24\u4e2a\u5de5\u7a0b\u961f\u540c\u4fee\u4e00\u6761\u516c\u8def\uff0c\u5b83\u4eec\u4ece\u4e24\u7aef\u540c\u65f6\u65bd\u5de5\u3002
\uff081\uff09\u7532\u961f\u6bcf\u5929\u4feea\u7c73\uff0c\u4e59\u961f\u6bcf\u5929\u4feeb\u7c73\uff0c8\u5929\u4fee\u5b8c\u3002\u8fd9\u6761\u516c\u8def\u957f\u591a\u5c11\u7c73?(\u65b9\u7a0b\u89e3\uff09
\u89e3\uff1a\u8bbe\u8fd9\u6761\u516c\u8def\u957fx\u7c73
x\u00f78=a+b
\u5bf9\u4e0d\u8d77\uff0c\u6211\u89e3\u4e0d\u51fa\u6765\uff0c\u6ca1\u6570\u636e\uff01
\uff082\uff09\u5982\u679c\u8fd9\u6761\u516c\u8def\u957f3000\u7c73\uff0c\u7532\u961f\u6bcf\u5929\u4fee85\u7c73\uff0c\u4e59\u961f\u6bcf\u5929\u4fee65\u7c73\u3002\u4fee\u5b8c\u8fd9\u6761\u516c\u8def\u9700\u8981\u51e0\u5929\uff1f\uff08\u65b9\u7a0b\u89e3\uff09
\u89e3\uff1a\u8bbe\u4fee\u5b8c\u8fd9\u6761\u516c\u8def\u9700\u8981y\u5929
\uff0885+65\uff09y=3000
y=3000\u00f7150
y=20
\u7b54\uff1a\u4fee\u5b8c\u8fd9\u6761\u516c\u8def\u898120\u5929
\u95ee\u4e00\u4e0b\uff0c\u4f60\u51e0\u5e74\u7ea7\u4e86\uff1f
文艺书是不变量,设为单位"1"
原来文艺书占全部的4/5,共630×4/5=504本
现在占7/10,所以,总数是:504÷7/10=720本.
共买来了科技书:720-630=90本
2.
奶糖为不变量,设为单位"1"
原来总量是奶糖的20/9,现在是4倍
奶糖有:16÷(4-20/9)=9块
1.(3/10×630-1/5×630)÷（1-3/10）=90
2.设奶糖有X块
(X÷9/20+16)×1/4=X
X=9
1. 1－1／5＝4/5
630 × 4/5 ＝504本
1－3/10＝7/10
504÷7/10＝720本
720－630＝90本
答: 又买来了90本科技书.
2. 1－9/20 ＝ 11/20
11/20÷9/20 ＝11/9
1－1/4＝3/4
3/4÷1/4 ＝3
3－11/9＝16/9
16÷16/9＝9块
答: 奶糖有9块.
绛旓細1銆佸伐绋嬮槦瑕佹寲涓鏉℃按娓狅紝鍏ㄩ暱3.3鍗冪背锛屽墠涓夊ぉ宸茬粡鎸栦簡1.2鍗冪背锛屼互鍚庣敱浜庢娊璋冧竴閮ㄥ垎浜哄弬鍔犲彟涓椤瑰伐浣滐紝姣忓ぉ灏戞寲100绫筹紝鎸栧畬杩欐潯姘存笭鍏敤澶氬皯澶╋紵1.2梅3=0.4鍗冪背 銆愬師鏉ョ殑宸ヤ綔鏁堢巼銆100绫=0.1鍗冪背 锛3.3-1.2锛壝凤紙0.4-0.1锛=2.1梅0.3 =7澶 銆愬墿涓嬬殑闇瑕佺殑鏃堕棿銆7+3=10澶 ...
绛旓細1,x+y=(x^2-y^2)/(x-y)=11 2.(n+2)^2=n^2+4(n+1)3.(1+1/2)*(1+1/2^2(浜岀殑浜屾鏂瑰垎涔嬩竴)*(1+1/2^4)*(1+1/2^8)*1/2^15 =(1-1/2)*(1+1/2)*(1+1/2^2(浜岀殑浜屾鏂瑰垎涔嬩竴)*(1+1/2^4)*(1+1/2^8)*1/2^15*1/(1-1/2)=(1-1/2^16)...
绛旓細1.鏈変竴鍧椾笁瑙掑舰鍦扮殑闈㈢Н鏄300骞虫柟绫炽傚鏋滃畠鐨勯珮鏄50绫筹紝搴曟槸澶氬皯绫筹紵300*2梅50=12锛堢背锛2.瀛︽牎鍑嗗鍦ㄤ竴鍧楅暱15绫炽佸12绫崇殑绌哄湴涓婂缓涓涓渾鏌卞舰鑺卞潧銆傚鏋滆浣胯姳鍧涚殑鍗犲湴闈㈢Н灏藉彲鑳藉ぇ锛岃繖涓姳鍧涚殑鍗犲湴闈㈢Н鏄灏戝钩鏂圭背锛12*1/2=6锛堢背锛3.14*6²=113.04锛堝钩鏂圭背锛3.涓涓棤鐩栫殑闀挎柟...
绛旓細璁惧叚骞寸骇涓鐝湁X浜猴紝鍏勾绾т簩鐝湁Y浜恒俋 - Y = 4 X - X/20 = Y + X/20 Y = X - 4 X - X/20 = X - 4 + X/20 X/10 = 4 X=40锛堜汉锛夎В9锛氳鍏矾鍏ㄩ暱涓篨鍗冪背銆40%X + 8.4 = X/2 X/2 - 2X/5 = 8.4 X/10 = 8.4 X=84锛堝崈绫筹級涔閬撻瑙ｇ瓟瀹屾瘯鈥︹...
绛旓細1銆傝В鏂圭▼锛2|x|=3 |x|=3/2 X=卤3/2 2.姣忓彧楦′袱鍙吙锛屾瘡鏉″厰瀛愬洓鍙紝鐜板湪鎶婅嫢骞插彧楦″拰鍏斿瓙鍏冲湪涓涓瀛愰噷闈紝鍏辨湁涓鐧炬潯鑵匡紝骞朵笖楦＄殑鍙暟鏄厰瀛愮殑涓夊嶏紝姹傞浮鍜屽厰瀛愬悇鏈澶氬皯銆傝楦℃湁X鍙 閭ｄ箞鍏斿瓙灏辨湁X/3鍙 鎵浠2X+4*X/3=100 X=30 鎵浠ラ浮鏈30鍙紝鍏斿瓙鏈30/3=10鍙 3.涓涓...
绛旓細1銆傛き鍦嗚繃涓鐐癸紝杩欎竴鐐规槸浠F2涓哄簳鐨勭瓑杈逛笁瑙掑舰鐨勯《鐐癸紙c/2锛屾牴鍙3脳c/2锛夛紝鐒跺悗浠ｅ叆姹傞渶瑕佺殑鏁板煎惂銆傛垨鑰呰繛鎺F1寰椾竴60搴︾殑鐩磋涓夎褰傜瓟妗堜负锛堟牴鍙3-1锛/2銆2.鐢卞唴鍒囧渾鍗婂緞鍙互绠楀嚭棰樹腑涓夎褰㈢殑闈㈢Н涓8锛屼粠鑰屼互f1f2涓哄簳鐨勯珮涓8/3锛8/3灏辨槸鎵姹傜旱鍧愭爣銆3.鍥涜竟褰㈣x杞村垎涓轰笂涓嬩袱涓...
绛旓細3銆傝1鍗冨厠棣欒晧x鍏冦 鏍规嵁棰樼洰锛4鍗冨厠鑻规灉鍜7鍗冨厠棣欒晧鐨勪环閽辩浉绛 鍙緱 7x=4*鑻规灉鍗曚环 鎵浠 鑻规灉鍗曚环=7x闄や互4 鍙 1鍗冨厠棣欒晧姣1鍗冨厠鑻规灉渚垮疁3.6鍏 鍙緱 7x闄や互锛4-x锛=3.6 瑙ｅ緱 x=4.8 绛旓細1鍗冨厠棣欒晧4.8鍏冿紝鑻规灉4.8+3.6=8.4鍏 濂戒簡锛岃繖鏄渶绠娲佹渶闈犺氨鐨勬柟娉曪紝甯屾湜浣...
绛旓細351000/400=877.5鍦 3銆佸ぉ瀹夐棬骞垮満鐨勯潰绉害涓44涓囧钩鏂圭背锛岃浼拌涓涓嬶紝瀹冪殑鐧句竾鍒嗕箣涓澶渤鐩稿綋浜庯紙 锛堿 鏁欏鍦伴潰鐨勯潰绉 B 榛戞澘闈㈢殑闈㈢Н C 璇炬闈㈢殑闈㈢Н D 閾呯瑪鐩掔洅闈㈢殑闈㈢Н 440000/1000000=0.44骞虫柟绫 閫塁 4銆佽瀵熶笅鍒楃瓑寮忥紙绛夊紡涓殑鈥滐紒鈥濇槸涓绉鏁板杩愮畻绗﹀彿锛夛紝1锛=1锛2锛=2*1锛3锛=...
绛旓細1. m+2鈮0锛宮鈮-2锛 閫堿 2. 3n+1=1-2n锛宯=0 閫塀 3. 2x-3=4k 1)(x-k)/2=k-3x 2)2)寮忓彉褰紝x-k=2k-6x 7x=3k x=3k/7 浠ｅ叆1)锛屽緱 6k/7-3=4k 6k-21=28k k=-21/22
绛旓細浜斻佸叚骞寸骇鐨勫簲鐢ㄩ锛氬叚骞寸骇鏈変笁涓彮,涓鐝笌浜岀彮鐨勫鐢熶汉鏁板拰姣斾笁鐝鐢熶汉鏁板3/4,浜岀彮涓庝笁鐝 鐨勫鐢熶汉鏁板拰姣斿叚骞寸骇瀛︾敓鎬绘暟2/3澶3浜,宸茬煡浜岀彮鏈夊鐢43浜,鍏勾绾у叡鏈夊鐢澶氬皯浜?涓涓渾閿ュ舰瀹瑰櫒涓鏈夋按4鍗囷紙椤剁偣鍚戜笅瑁呮按锛夛紝杩欐椂姘撮潰楂樺害姝ｅソ鏄渾閿ラ珮搴︾殑1/2锛屾按闈㈠崐寰勬槸瀹瑰櫒鍗婂緞鐨1/2锛...
