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1、二元一次方程组计算练二元一次方程组计算练习 一用代入法解下列方程组: x=y-50x+3y=72x+y=3x+2y=2 (1) (2) (3) (4)3x-5y=11x+y=180y-x=12x+y=7 y=3xx=2y-3x-3y=5y=x-3(5) (6) 7x-2y=27x+5y=62x+y=5y-2x=5 2x-y=5x-2y=09m-2n=32p-3q=13 x+y=1x=3y+14n+m=-1-p+5=4q x=73y-2x=4 y-12y+22x=+13x=y-x+1=2y, 3 2(x+1)-y=11;二用加减法解下列方程组: 4x+3y=73m+2n=16,2x+3y=4,5
2、x-2y=3,(1) 3m-n=1;4x-4y=3; x+6y=11; 4x-3y=5mnx+3y+5+=7,+=23x+2y=5x+22362x-3y=33 (5) (7) (8) x-42y-3mn2(3x+2y)=2x+83x+2y=11+=2 +=2.5344 3x+5y=193m-2n=53x-5y=76x-5y=11(9) 4x-3y=64m+2n=94x+2y=5 -4x-4y=712111x-9y=125x+2y=5ax+y=5 ( a为常数) 35-4x+3y=-53x+4y=3a 0.5x-0.3y=0.23x-5z=6,(16) (17) x+4z=-15; m-n=2,
3、 2m+3n=14;三、用适当的方法解下列方程 111x-y=120.4x+0.3y=0.7x-y+1=04m-2n+5=023 5 3123n-4m=611x-10y=1-x-y= 2x+2y=73 3 (9)、x+y=5 (10)、3x-5y=6 (11) 2x-4y=81、x=1.2y (8) 2 x - y=65x-4y=122x+31y=-11x-y=1x+4y=-15 (12) 3x+5y=5 3x-8y-10=03x-4y=236b=-34x-3y=54a-ab (15) =4x+6y=1434 m-12n+4-=6=32 342x+3y=13y 4m-3n=7 x-=9x+3y=112 xymn+=244mn+=2636b=-34a-4x-3y=5 (21) 3x+5(x+y)=3y+4(x+y)=36 a b =4x+6y=14 34 xy= 2 325%x+15%y=1.252x-13y-2xyxy+1+=2,+=7,-=1,5434 (32) 32213x+1-3y+2=0.3x+2y=10;x+y=14;42534x-3y=54x+6y=14