三元一次方程组2x=3y=6z-搜答案-拍题作业网

x=2y=1z=-1再问：亲！～～求过程啊！～～再答：(1)+(3)得3x+5y=11（2）+2（3）得3x+3y=9联立的y=1x=2带入（1）得z=-1

由x+y/3=x+z/2得：y/3=z/2z=2y/3(1)由x+z/2=y+z/2得：x=y(2)把(1)和(2)代入x+y+z=28得：y+y+2y/3=288y/3=28y=21/2把y=21/

我知道了,你打算问那题我就打那题再问：这三题都不会再答：第一题：x+y+z=6(1)x-z=2(2)2x-y+z=5(3)(1)+(3)3x+2z=11(4)(2)×2+(2)2x+3x=4+115x

解题过程如下,希望对你有所帮助：

由x:y=2:1得x=2y,代入2x-y=3z,可得3y=3z,z=y于是x+y+z=2y+y+y=20,y=5,x=10,z=5于是x=10,y=5,z=5

3y=2z->y=(2/3)z3x-z=0->x=(1/3)zx+y+z=(1/3)z+(2/3)z+z=6->2z=6z=3->y=2->x=1

再问：字挺漂亮的，谢谢啦

设（x+y)/2=y+z/3=z+x/4=k∴x+y=2k,y+z=3k,x+z=4k∴2x+2y+2z=9k∵x+y+z=27∴k=6∴z=27-2×6=15x=4×6-15=9y=2×6-9=3

此方程解为[x=6,y=-12,z=4]

①+③：4x+5y=14④①*3-②:2x+y=4⑤④-2*⑤:3y=6,得y=2代入⑤：x=(4-y)/2=1代入①：z=6-x-y=3故x=1,y=2,z=3

x:y=3:2,则x=y*3/2y:z=5:4,则z=y*4/5x+y+z=y*3/2+y+y*4/5=y*(3/2+1+4/5)=y*33/10=6所以y=20/11则x=y*3/2=30/11z=

3x=3y=6z=>x=y=2z设x=a则y=a,z=2ax+2y+z=16a+2a+2a=165a=16a=16/5x=16/5y=16/5z=32/5

x:y:z=1:2:3x+y+z=36、x=ay=2az=3aa+2a+3a=36a=6x=6y=12z=18

3x+2y+5z=2①x-2y-z=6②4x+2y-7z=30③①+②得4x+4z=8→x=2-z④③-①得x-12z=28→x=28+12z⑤④⑤得z=-2得x=4得y=0X=4Y=0Z=-2再问：

5x+2y-3z=2①x+2y+z=6②7x-2y-4z=26③①-②得：x-z=-1④②+③得：8x-3z=32⑤④*2-⑤得：-8z+3z=-8-32z=8⑥将⑥代入④得：x=-7⑦再将⑥⑦代入①

3x-5y+6z=4(1)3x-2y+2z=3(2)-3x-3y+5z=-1(3)(1)-(2)-3y+4z=1(4)(2)+(3)-5y+7z=2(5)5(4)-3(5)z=1from(4)y=1f

x+y+z=6(1)y-z=4(2)x-y-2z=3(3)(1)-(3)=2y+3z=3y-z=42y-2z=8联立得z=-1,y=3,x=4

x+y-z=6标记为A,y+z-x=2标记为B,z+x-y=0标记为C,A+B：2Y=8Y=4A+C：2X=6X=3B+C：2Z=2Z=1然后就是结论.回答完毕.最完整的~

x+2y=2(1)2y+3z=4(2)x+3z=6(3)(1)+(2)+(3)2x+4y+6z=12x+2y+3z=6(4)(4)-(1)得3z=4z=4/3(4)-(2)得x=2(4)-(3)得2y

由x:y:z=1:2:3可得y=2x,z=3x代入x+y+z=36得6x=36于是x=6,y=12,z=18