用代入法解下列方程.(1){3x=4y,4x-5y=3 (2){3(x-1)=y+1,2(y-1)=4(x+2)

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用代入法解下列方程.(1){3x=4y,4x-5y=3 (2){3(x-1)=y+1,2(y-1)=4(x+2)

用代入法解下列方程.(1){3x=4y,4x-5y=3 (2){3(x-1)=y+1,2(y-1)=4(x+2)
用代入法解下列方程.(1){3x=4y,4x-5y=3 (2){3(x-1)=y+1,2(y-1)=4(x+2)

用代入法解下列方程.(1){3x=4y,4x-5y=3 (2){3(x-1)=y+1,2(y-1)=4(x+2)
(1)x=4/3y代入4x-5y=3 得x=12 ,y=9
(2)3(x-1)=y+1拆开得 3x-3=y+1 所以y=3x-4,代入2(y-1)=4(x+2)
解得x=9 ,y=23

1.X12Y9

3x=4y,x=(3y)/4,代入4((3y)/4-5y=3,x=2,y=-1.5
y=3x-4,代入6x-10=4x+8,x=9,y=23