帮忙讲讲一道初二实数题
\u95ee\u4e00\u9053\u521d\u4e8c\u5b9e\u6570\u9898\u8fd9\u9898\u6709\u6f0f\u6d1e\uff0c\u5f533<=a\u9009D\uff0c\u5f531<=a<=2\u65f6\u662fACB\uff0c\u5f532<=a<=3\u9009ABC\uff0c\u663e\u7136\u8fd9\u9898\u6709\u6f0f\u6d1e\uff0c\u4f46\u662f\u8fd9\u4e09\u79cd\u60c5\u51b5\u53ea\u6709D\u9009\u9879\uff0c
\u6240\u4ee5\u52c9\u5f3a\u9009D
\u6570\u8f74\u662f\u4ece\u5de6\u5f80\u53f3\u8d8a\u6765\u8d8a\u5927
\u4e14a\u80af\u5b9a\u5c0f\u4e8ea+2/3\u6240\u4ee5\u524d\u4e09\u4f4d\u7684\u56de\u7b54\u90fd\u662f\u9519\u8bef\u7684\uff0c\u6240\u4ee5AB\u53ea\u6709A\u5728\u5de6B\u5728\u53f3\u8fd9\u4e00\u79cd\u60c5\u51b5\uff0c\u7b2c\u4e09\u4f4d\u7684\u56de\u7b54\u662f\u6709\u9053\u7406\u4f46\u662f\u8fd9\u9898\u52c9\u5f3a\u9009D
1.\u5df2\u77e5x\u7684\u7acb\u65b9\u6839=3\uff0c\u4e14\uff082y-3z+2)^2+\u6839\u53f7z-4=0
\u6c42x+y^3+z^3\u7684\u7acb\u65b9\u6839\u7684\u503c\u3002
x\u7684\u7acb\u65b9\u6839=3\uff0c\u6240\u4ee5x=27
\uff082y-3z+2)^2+\u6839\u53f7z-4=0\uff08\u611f\u89c9\u4e0d\u592a\u5bf9\uff0c\u5e94\u8be5\u662f\u201c\u6839\u53f7\uff08z-4\uff09\u201d\uff09
\uff082y-3z+2)^2\u548c\u6839\u53f7\uff08z-4\uff09\u90fd\u4e0d\u5c0f\u4e8e0\uff0c\u800c\u4e24\u8005\u548c\u4e3a0\uff0c\u6545\u90fd\u7b49\u4e8e0
\u5373\uff082y-3z+2)^2=\u6839\u53f7\uff08z-4\uff09=0\uff0c\u5f97z=4\uff0cy=5
x+y^3+z^3=27+5^3+4^3=27+125+64=216
x+y^3+z^3\u7684\u7acb\u65b9\u6839=6
2.\u5c06\u4e00\u5757\u4f53\u79ef\u4e3a0.125\u5e73\u65b9\u5398\u7c73\uff08\u7acb\u65b9\uff1f\uff09\u7684\u7acb\u65b9\u4f53\u94dd\u5757\u6539\u94f8\u62108\u4e2a\u540c\u6837\u5927\u5c0f\u7684\u7acb\u65b9\u4f53\u5c0f\u94dd\u5757\uff0c\u6c42\u6bcf\u4e2a\u5c0f\u7acb\u65b9\u4f53\u94dd\u5757\u7684\u8868\u9762\u79ef
\u8bbe\u5c0f\u7acb\u65b9\u4f53\u7684\u8fb9\u957f\u662fa\uff0c\u7531\u5c0f\u7acb\u65b9\u4f53\u4f53\u79ef\u548c\u7b49\u4e8e\u539f\u7acb\u65b9\u4f53\u4f53\u79ef\uff0c\u53ef\u5f97
8\u00d7a^3=0.125\u7acb\u65b9\u5398\u7c73\uff0c\u89e3\u5f97a=1/4 \u5398\u7c73\uff0c\u8868\u9762\u79efs=6\u00d7a^2=\u516b\u5206\u4e4b\u4e09\u5e73\u65b9\u5398\u7c73
3.\u6839\u53f732-\u6839\u53f78\u5206\u4e4b1+5\u5206\u4e4b1\u500d\u6839\u53f775-3\u500d\u6839\u53f73\u5206\u4e4b1+\u6839\u53f72\u5206\u4e4b4
=4 \u68392 - 1/4 \u68392 + 5\u5206\u4e4b5\u500d\u6839\u53f73 - \uff08\u540e\u9762\u8fd9\u4e9b\u5206\u5f0f\u5728\u6839\u53f7\u91cc\u9762\u8fd8\u662f\u53ea\u6709\u5206\u6bcd\u5728\u6839\u53f7\u91cc\u9762\uff1f\u9ed8\u8ba4\u4e3a\u201c-3\u500d\u6839\u53f7\uff083\u5206\u4e4b1\uff09+\uff08\u6839\u53f72\uff09\u5206\u4e4b4\u201d\uff09 \u68393 +2 \u68392
=\uff084 \u68392 - 1/4 \u68392 +2 \u68392\uff09 + \uff085\u5206\u4e4b5\u500d\u6839\u53f73 - \u68393\uff09
=23/4 \u68392 + 0 = 23/4 \u68392
4.-\uff08-2\uff09^-2+\u6839\u53f7\uff08\u6839\u53f73+2\uff09^2-(\u6839\u53f73+2\uff09^0+|3\u5206\u4e4b\u6839\u53f73-2\u5206\u4e4b\u6839\u53f73|\u9664\u4ee53\u5206\u4e4b2\u4e58\u4ee54
=-1/4 + \uff08\u6839\u53f73+2\uff09 - 1 + |-6\u5206\u4e4b\u68393|/2 \u00d73\u00d74
=-1/4 + \u6839\u53f73 + 2 - 1 + \u68393
=3/4 + 2\u68393
5.125x^3-y=20\uff0c\u6839\u53f7y=14.\u6c42x
\u6839\u53f7y=14\uff0c\u6240\u4ee5y=196\uff0c\u4ee3\u5165125x^3-y=20\uff0c\u5f97x^3=216/125\uff0cx\u7684\u503c\u4e3a5\u5206\u4e4b6.
\u5e73\u65f6\u591a\u505a\u9898\uff0c\u591a\u7ec3\u4e60\uff0c\u8fd9\u4e9b\u4e0d\u96be\u7684\u3002
见图。
3√1-11/27
=3√16/27
=3√2*8/27
=3√2*(2/3)三次方
=2/3*3√2
3根号（1-11/27）=3根号（27/27-11/27）=3根号（16/27）=3根号（2的4次方/3的3次方）=3根号（2*2的三次方/3的3次方）=3根号（2*三分之二的三次方）=三分之二*3根号下2
绛旓細(1)x^2-9x+8=0 绛旀锛歺1=8 x2=1 (2)x^2+6x-27=0 绛旀锛歺1=3 x2=-9 (3)x^2-2x-80=0 绛旀锛歺1=-8 x2=10 (4)x^2+10x-200=0 绛旀锛歺1=-20 x2=10 (5)x^2-20x+96=0 绛旀锛歺1=12 x2=8 (6)x^2+23x+76=0 绛旀锛歺1=-19 x2=-4 (7)x^2-25x+154=0 ...
绛旓細4:鐢遍鐭+3=15-2a寰梐=4锛屾晠骞虫柟鏍筧+3=7鎴2a-15=-7锛岄偅涔堣繖涓暟绛変簬锛49 锛5锛氬綋X锛 =-1 锛夋椂锛屾牴鍙稾+1鍒嗕箣4鏃犳剰涔夛紝鍥犱负鍒嗘瘝涓洪浂 6锛氣垰a+1 +2鐨勬渶灏戝兼槸锛2 锛夛紝姝ゆ椂a鐨勫彇鍊兼槸锛 -1 锛.鍥犱负鈭歛+1>=0褰揳=-1鏃跺彇寰楁渶灏忓0锛屾晠锛氣垰a+1 +2鐨勬渶灏戝2...
绛旓細鈭达紙y+z锛壜穢^2=1/4脳1/4=1/16 14銆佽繖棰鎵撳嵃閿欎簡锛屽叾涓竴涓獂搴旇鍐欐垚y锛屼笉璁烘槸鍝釜缁撴灉閮戒竴鏍枫傜敱棰樻剰鐭ワ紝3鈭氾紙3x-7锛=-3鈭氾紙3y+4锛夆埓3x-7=-(3y+4)绉婚」锛屽緱3x+3y=3 鈭磝+y=1 瑕佸浼氬埄鐢ㄧ粷瀵瑰煎拰鏃犵悊寮忕殑鎬ц川鍟婏紝鍙鐭ラ亾寮忓瓙閲岀殑缁撴灉涓瀹氳澶т簬绛変簬0锛屽墠涓ら亾棰樺氨浼氬仛浜嗐...
绛旓細鑳戒笉鑳界湅鎳傘2鈭8鍖栫畝涓2鈭氾紙2*4锛夊彲浠ユ妸4鑴卞嚭鍘伙紝鍗2*2鈭2=4鈭2 鍏朵粬鐨勫悓鐞嗭紝杩欐牱鐨勯鍏堝寲绠锛屾妸鏍瑰紡閲岄潰鐨勬暟鍖栫畝锛岃嚦浜庢庝箞鍖栫畝灏辩湅鏄紑鍑犳鏍瑰紡浜嗭紝寮2娆℃牴寮忓氨鎶婇噷闈㈡槸骞虫柟鏁扮殑鍏堣劚鍑烘潵锛屽紑3娆℃牴寮忓氨鎶婇噷闈㈡槸绔嬫柟鏁扮殑鍏堣劚鍑烘潵 ...
绛旓細1.3鈭氾紙1/6锛-4鈭氾紙50锛+30鈭氾紙2/3锛 绛旀3鈭氾紙1/6锛-4鈭氾紙50锛+30鈭氾紙2/3锛 = 3脳鈭6/6-4脳5鈭2+30脳鈭6/3 锛濃垰6/2-20鈭2+10鈭6 2. 锛1-鏍瑰彿2锛/2涔樹互锛1锛嬫牴鍙2锛夛紡2 棰樻槸杩欐牱鐨勪簩鍒嗕箣涓鍑忔牴鍙2涔樹互浜屽垎涔嬩竴鍔犳牴鍙2 绛旀锛氾紙1-鏍瑰彿2锛/2涔樹互锛1锛嬫牴鍙2锛夛紡...
绛旓細鍥炵瓟锛氫袱涓潪璐瀹炴暟鐨勫拰涓0,鍒欒繖涓や釜鏁伴兘绛変簬0,鎵浠 a=鈭3, b=1 2/a²b=2/3
绛旓細鈭(1+X)+(1-Y鈭(1-Y)=0锛屸埖1+X鈮0锛1-Y鈮0锛屸埓X+1=0锛1-Y=0锛屸埓X=-1锛孻=1锛屸埓鍘熷紡=-1-1脳(-1)-1 =-1銆
绛旓細锛-11.28锛+锛-3鍙5/11锛+锛+7.28锛-锛+4鍙6/11锛夛紙2锛-2鍙3/4+8鍙7/8-3鍙3/4-5鍙5/8 锛3锛2/3-1/8-锛-1/3锛+锛-3/8锛夛紙4锛75梅銆138梅锛100-54锛夈 85脳(95锛1440梅24)锛5锛80400锛(4300锛870梅15) 240脳78梅锛154-115锛夛紙6锛1437脳27锛27脳563 銆75-锛...
绛旓細1.灏鸿浣滃浘锛熶互锛0锛1锛変负鍦嗗績锛2涓哄崐寰勪綔鍦嗭紝涓嶺杞翠氦鐐瑰氨鏄牴鍙3锛屾牴鍙5鍦紙0锛2锛変綔鍗婂緞3鐨勫渾銆2.x^2+y^2-2xy-14x+14y+49=(y-x+7)^2=0,y=x-7,2x-3y+5=0 x=26,y=19 x^2-y^2=315
绛旓細杩欓涓昏鑰冪粏鑺傦細鏍瑰彿锛3x锛1锛夛紜6*鏍瑰彿(1-3x)+6=y 瑕佹槸涓や釜鏍瑰彿閮芥湁鎰忎箟锛屽繀椤 3x-1>=0,x>=1/3 1-3x>=0,x<=1/3 鎵浠=1/3 鎵浠ュ甫鍏ワ紝寰梱=6
