急急急!初一年级二元一次和三元一次方程组问题1-0.3(y-2)=5分之x+1四分之y-1=20分之4x+9再-12分之3x-1 -3分之x-y=14分之x-y+3分之x+2y=10.4x+0.3y=2.43分之x-3=5分之y+63(y-2)=x-172(x-1)=5y-8x+y=7y+z=8z+x=92x+y-3z=33x-y+2z=-1x-y-z=5要求:过程详解,越详细,分越多,记住
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1.化简(1):10/10-3/10y+6/10=x+2/10
x=14/10-3/10y
化简(2):y-5/20=4x+9/20-20/20+5/20
y=4x-6/20
将(1)带入(2)中,得:
y=4(14/10-3/10y)-6/20
y=28/5-6/5y-6/20
y+6/5y=112/20-6/20
y(5/5+6/5)=106/20
y=53/22
将y带入(1)中,得:
x=14/10-3/10*53/22
x=14/10-159/220
x=308/220-159/220
x=149/220
2.看不懂3.0.4x+0.3y=2.4
两边乘104x+3y=24 (1)
(x-3)/3=(y+6)/5
所以5(x-3)=3(y+6)
5x-15=3y+18
5x-3y=-33 (2)
(1)+(2)
9x=-9x=-1y=(33+5x)/3=28/34.3(y-2)=x-17,3y-6=x-17所以x=3y+11代入2(x-1)=5y-82(3y+11-1)=5y-86y+20=5y-8y=-28x=3y+11=-735.6.2x+y-3z=3,①3x-y+2z=-1
,②x-y-z=5
③①+②:5x-z=2 ④②-③:2x+3z=-6 ⑤④*3+⑤:17x=0x=0代入④:z=-2x=0,z=-2代入③:0-y-(-2)=5y=-3得到x=0,y=-3,z=-2 下面两个贼人 怎么干这事