解方程组19X加18Y=17
来源:学生作业帮助网 编辑:作业帮 时间:2024/09/23 20:17:22
x^2+y^2+x+y=18(1)x^2+xy+y^2=19(2)设:u=x+yv=xyx^2+y^2+u=18(3)x^2+y^2+v=19(4)u^2-2v+u=18(5)u^2-2v+v=19u
3分之y-6分之(x+1)=3①①×6得:2y-x=19(3)②×6去括号得:6x+7y=0(4)把(3)x=2y-19代入(4)得19y=114y=6把y=6代入x=2y-19得x=-7
1、加减消元法!X=3/48Y=3/40Z=82、设甜果9x个,苦果7y个9x+7y=100011x+4y=999解得x=73y=49故甜果为9*x=657苦果为7*y=343
4x-3y=7①(x-1)/3=(2y+3)/4②②两边乘以12,得4(x-1)=3(2y+3)4x-6y=13③①-③,得3y=-6y=-2代入①中,得x=1/4x=1/4y=-2
x+y=sxy=tx^2+y^2=(x+y)^2-2xy=s^2-2tx*2+y*2+x+y=18x*2+xy+y*2=19s^2-2t+s=18(1)s^2-2t+t=9(2)由(1)得:t=(s^
3x+2y=2m+5(1)2x-y=4(2)x+y=5(3)由题意,满足(2)(3)同样满足(1)(2)+(3)3x=9x=3,y=2代入(1)3*3+2*2=2m+513=2m+5m=4
6x+7y=﹣19(1)5y-6x=﹣17(2)(1)+(2)得12y=-36y=-3代入(1)得6x-21=-196x=2x=1/3
2分之2x+y加3分之2x-y=1,——》10x+y=6,.(1)4*(2x+y)-5(2x-y)=8,——》9y-2x=8,.(2)(1)+(2)*5,得:46y=46,即y=1,代入(1),得:x
2/(x+y)+5/(x-y)=189/(x+y)-10/(y-x)=66设x+y=a,x-y=b,原方程化为2/a+5/b=18-----1(1)9/a+10/b=66-------(2)(2)-(
x(x+y+z)=6(1)y(x+y+z)=12(2)z(x+y+z)=18(3)(1)/(2)x/y=1/2y=2x(1)/(3)x/z=1/3z=3xx(x+2x+3x)=66x^2=6x=1y=
另a=1/(x+y),b=1/(x-y);则2a+5b=18;9a+10b=66;解得a=6,b=6/5;即 &nbs
x+y=15x=15-y(x+15%x+y+10%y)=171.15x+1.1y=17115x+110y=1700115(15-y)+110y=17001725-115y+110y=17005y=25
x+2y=1(1)3x-2y=11(2)(1)+(2)4x=12x=3y=-1
解x+y=17①x+z=18②y+z=19③②-①z-y=1④④+③2z=20∴z=10∴y=9∴x=8
{3分之y减6分之x加1=3,2(x-2分之y)=3(x加18分之yy/3-(x+1/6)=32y-6x=19(1)2(x-y/2)=3(x+y/18)2x-y=3x+y/612x-6y=18x+y6
首先,题目出了点小错,让我们改一下把第三个式子改成x+z=19然后就可以解了~x+y=-14①y+z=-7②x+z=19③①+②+③得2x+2y+2z=-2x+y+z=-1④④-③得y=-20④-②得
x-y+z=02x+y-2z=6x=z-y2x=6-y+2z代入2(z-y)=6-y+2z2z-2y=6-y+2z-2y=6-yy=-6再答:后面自己应该能算了吧,手机打字真辛苦再问:嗯谢谢你了再问:
√3x-√2y=5①√2x+√3y=5②①×√3+②×√2,解得x=√3+√2②×√3-①×√2,解得y=√3-√2
再问:是加减法不是代入法再答:马上哦…………嘿嘿再问:快点谢了再答:x=5哦!!写错了记得采纳哦!嘿嘿…………
因为8/(x+y)+18/(x-y)=4/3,两边乘以3得24/(x+y)+54/(x-y)=4两边同时减去24/(x+y)+24/(x-y)=7/3得30/(x-y)=5/3所以x-y=18代入8/