1:b=3-2a, 代入得:3a+3-2a=4,a=1,b=1
2:y=4x-3,代入得:2x-5(4x-3)=-3,2x-20x+15=-3,18x=18,x=1,y=1
3:y=3-2x,代入得:x/2-1.5(3-2x)=-1,0.5x-4.5+3x=-1, 3.5x=3.5,x=1,y=1
暂时没有该问题的其它回答(1)用代入法解方程组(2)用加减法解方程组.
gegorlove1B9
(1),由①得:x=y+3,代入②得:3y+9-8y=14,解得:y=-1,将y=-1代入得:x=-1+3=2,则方程组的解为;(2),①×2+②×3得:17x=51,即x=3,将x=3代入①得:12+3y=3,即y=-3,则方程组的解为.
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扫描下载二维码用代入消元法解下面的方程组 4x-3y=14 , y=7-x 2x-5y=19 , y-3x=1.2_百度知道
用代入消元法解下面的方程组 4x-3y=14 , y=7-x 2x-5y=19 , y-3x=1.2
提问者采纳
2+3x=-297/, y-3x=1.2
②由②,得 4x-3*(7-x)=14,化简得 7x=35;13y=14x-3y=14 .22x-5y=19
①-3x+y=1,x=5y=7-x=2因此 x=5
y=22x-5y=19 ;5+3x)=19;65希望能有帮助, y=7-x4x-3y=14
②②代入①,得 2x-5*(6/,化简得 -13x=25得 x=-25/,得y=6/5+3x代入①
提问者评价
thank you very much!
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