解下列方程组2x加3y加z=11
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1)x+y-z=-3①2x+y-3z=-2②3x-y+2z=-11③②+③得:5x-z=-13z=5x+13④②-①得:x-2z=1⑤④代入⑤得:x-10x-26=1x=-3z=5x+13=-2将x=
(1)x+y=3,y+z=5,x+z=4三式相加:x+y+y+z+x+z=2(x+y+z)=12x+y+z=6x+y=3,z=3y+z=5,y=2,x+1(2)设x=2k,y=3k,z=5k2x+y+
(1){y=2x-1,①2x+3y+z=8,②3x+2y=-4③①代入③,得3x+4x-2=-47x=-2x=-2/7代入①,得y=-4/7-1=-11/7从而z=8-2x-3y=8+4/7+33/7
4x+9y=12(1),3y-2z=1,(2)7x+5Z=19/4(3)等价于:28x+20z=19(4)(1)-3*(3)得4x+6z=9(5)由(4)(5)联立得:z=2带入(2)得:y=5/3带
2x-5y=34x-5y=6与2式相加4x-5y-4x+y=6-3-4y=3y=-3/42x=5y+3=-3/4x5+3=-3/4x=-3/8如果本题有什么不明白可以追问,再问:晚了伙计算了
2X+3Y=6(1)3X-2Y=-2(2)(1)乘以3得到:6X+9Y=18(3)(2)乘以2得到:6X-4Y=-4(4)(3)减去(4)得到:13Y=22Y=22/13把Y=22/13代入(1)得到
第一题3x-y+z=3①;2x+y-3z=11②;x+y+z=12③;①减③2X-2Y=-9④;3倍的③即3X+3Y+3Z=36⑤;⑤加②5X+4Y=47⑥;2倍的④4X-4Y=-18⑦;⑥式加⑦9X
1.z=38-2x-3y3x+4y+2(38-2x-3y)=56-x-2y=-20x+2y=204x+5y+38-2x-3y=662x+2y=28x+y=14y=14-xx+2(14-x)=20-x=
(1)x-z=4,①x+y-z=-1,②2y-z=1③②-①得:y=-5代入③:-10-z=1-z=11z=-11代入①:x+11=4x=-7所以,x=-7,y=-5,z=-11
1、y=2z+1,x=-1-3z代入:3x-5y+z=21得:3(-1-3z)-5(1+2z)+z=21-3-9z-5-10z+z=21-18z=29z=-29/18x=-1-3×(-29/18)=-
3x-y-4z=5y=3x-4z-5代入另两个x+3x-4z-5+z=2即4x-3z=3(1)2x+3(3x-4z-5)-2z=011x-14z=15(2)由(1)z=(4x-3)/3代入(2)11x
x/2=y/3=>x=2/3y-------(1)y/3=z/5=>z=5/3y------(2)将(1)(2)代入3x-y+2z=26中3*2/3y-y+2*5/3y=y+10/3y=13/3y=2
x-2y=-4即x=2y-4……(1)y-z=1即z=y-1……(2)代(1)、(2)入2z+3x=10得2(y-1)+3(2y-4)=10y=3所以x=2,z=2
(1)+(2)得2x+2y=18x+y=9(4)(2)+(3)得2x-y=0(5)(4)+(5)得3x=9∴x=3把x=3代入(4)得3+y=9∴y=6把x=3,y=6代入(1)得3+6+z=18∴x
x:y:z=1:2:3(1)2x+y-3z=15(2)可设x=t,y=2t,z=3t,代入(2)式得:2t+2t-9t=15-5t=15t=-3所以x=-3y=-6z=-9第二题正确题目应是:2x+y
x-2y=4①3x-3y+2z=1②x+y-z=5③③*2得:2x+2y-2z=10④ ②+④得:5x-y=11⑤ ⑤*2-①得:9x=18 ∴x=2 将x=2代入①得:2-2y=4 ∴y=
(2)*2+(1)得13x+6y=24与(1)联立解得x=25分之66代入(3)解得z=负50分之49代入(2)得y=负25分之43
x-y-z=1……①2x+y-3z=4……②3x-2y-z=-1……③①+②可得3x-4z=5……④③-2①可得x+z=-3……⑤联立④⑤方程可得x=-1,z=-2把x=-1,z=-2代入①方程可得y
2x+y=6(1)3x-y=4(2)(1)+(2)得5x=10∴x=2把x=2代入(1)得4+y=6y=2∴方程组的解是x=2y=2再问:怎样写这道题再答:就是象我上面写的这样呀,请采纳,谢谢再问:方