2100x+700y=84;900x+2700y=180的解韪步骤
问题描述:
2100x+700y=84;900x+2700y=180的解韪步骤
答
2100x+700y=84,两边除700化简,得3x+y=0.12……1
900x+2700y=180,两边除900化简,得x+3y=0.2……2
方程1乘以3得:9X+3Y=0.36......3
方程3-方程2得:X=0.02
把X=0.02代入方程2得:Y=0.06
答
2100x+700y=84,两边除700化简,得3x+y=0.12……①式
900x+2700y=180,两边除900化简,得x+3y=0.2……②式
两式相加,4(x+y)=0.32,即x+y=0.08……③式
①-③,得2x=0.04,故x=0.02
②-③,得2y=0.12,故y=0.06
答
2100x+700y=84 (1)
900x+2700y=180 (2)
化简得
150x+50y=6 (3)
150x+450y=30 (4)
(4)-(3)
y=0.06
代入(3)得
x=0.02
答
1) 2100x+700y=84
2) 900x+2700y=180
化简:
3) 525x+175y=21
4) 5x+15y=1
3)-4)*105:-1400y=-84,y=3/50=0.6
代入4):x=1/50 =0.02