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1、培优训练四:二元一次方程组计算及基础训练、用代入消元法解下列方程组:1.(2x+9y=81a(3x+y=34aa2.(9x+4y=35a(8x+3y=30aA3.J7x+2y=52a
2、7x+4y=623A4.(4x托y=54al9x+2y=873A5.
3、2x-Fy=73i2x+5y=19aAI6.x+2y=213,3x+5y=563al7.5x+7y=52a■5x+2y=22a8.5x+5y=6537x+7y=2033►9.>8x+4y=563'x+4y=21310.
4、5x+7y=413l5x+8y=443I11.7x+5y=54a,3x+4y=38a12.x+8y=15w■4xt
5、y=29aa13.3x+6y=24a■9x+5y=46wi14・'9x+2y=623'4x+3y=36aI15・'9x+4y=463'7x+4y=42aIA16.9x+7y=135a,4x+y=41317.3x+8y=51aX托y=27318・9x+3y=9934x+7y=95®»19・9x+2y=383'3x-^y=18a20・’5x+5y=453'7x+9y=69a►I21.8x+2y=283(7x+8y=62aA22.x+6y=14w3x+3y=27323・7x+4y=6732x+8y=26324.‘5x+4y=52a"7x-^y=74aId25・
6、7x+y=^3(4x托y=
7、16aa26.(6x托y=48al6x+3y=42a27.(8x+2y=16a[7x4y=ll328.j4xTy=77a托y=94329・J6x+8y=68a托y=66a30.(2x+2y=223l7x+2y=47^a»31.5x+3y=82,3x+5y=8aa»32.6x-7y=5a■x+2y=4333・(10x-8y=14^■x+y=53i34.J4x+7y=3u1x+y=Oa35.f3x+y=10ai7x^y=20aa36.(44x+10y=27^(x4y=l337・f8x-y=O^[x4y=18aa38.fllx^=12^
8、lly-x=-123a39.j5x+6y=27*J
9、(2x+3y=12a40.7x-2y=4^*x+2y=123I41.
10、(2x4y)-5y=2^l2x-5y=O342.7x-3y=3>Ja3x+2y=213a43.卩x+2y=22■y-6x=l344・flOx-SyO^
11、3x-2y=2345.(3x+y=10d
12、5x-7y=8Aa46・P3x-2y=la
13、x-y=3^47.fx+3y=-5A
14、3x-4y=-2^a48.Jy-3x=2+JU-2y=6^A49.f5x+3y=2dl2x-y=3aa50.J9x-3y=12u12x+y=6dA51.2x+3y=23x+2y=3aI52・3x+2y=18aax+y=7^二、用加减消元法解下
15、列方程组:1.2x-5y=l2.x+8y=4423.3x~2y=54.3x-5y二2x+y=35x+6y=4807x-4y=l12x-y=35.4x-3y二186.x-2y二57.3x+y二78.3x-2y二72x-y=8x+3y=_52x+3y=72x-3y=3fx+3y=4'(2x-3y=-l3x+4y=95x+y=4ll.ggll[2x+y=1312J4x+3y=10[x+4y=913l2011x-2012y=2010*12010x-2009y=201114.2x+3y=7x_3y=815.3兀+2y=56x-5y=i十1=0[x+3y+10=018.J4X=1[2x-y=3
16、y19.x-y=12x+y=563-5尸6[x+4y=-15J9x+4y=120.[x+6y=-ll21.x+2y=-57x-2y=1322・F»33x-Sy=1323.3x+4y=19x-y=424.P=，-X[3x+2y=5三.选择合适的方法解下列方程组:1.严1[2x+y=3〔3(x-4)=4(jH-2)2j2x-3y=-5•t3x+2y=12十讣(汀1)3x-2(2y+l)二4严?=为已知数)44x-4y=6a3x一4y=27.竺口二232乙2x-11•y8I4j+l)+y(l-x)=2[x(x+l)-y―兀？=0X一y=49,
17、4x+2y=-110.(9x+2y=20(3
18、x+4y=1032=113.16.3x-2(x+2y)=3llx+4(x+2y)=4514.■f中3(x+y)+2(x-3y)二15(x+4y=1415-'x-3_y~343=12x+yx-y2计3h4(x+y)-5(x-y)X-25-y2~3=1旦上二50.20.3"°(x+y=l[20%x+30%y=25%X23(s_t)-2(s+t)=103(s_t)+2(s+t)=26fx+y=lI2x+y=3J2x-3y=-5'[3x+2y=124=424.24=5334x
