用代入法解下列方程组,注意事项:不要浪费时间讲道理,(1)x=2分之3,2x-y=8.(2)2x-3y=7,y=3x.(3)m-2n=8,4(m-2n)+n=30.(4)3x+2y=7,5x-4y=-3.(5)2(x+y)-3(x-y)=1,6(x+y)+7(x-y)=51.(1)如果x=7,y=1是方程组3x-ay=16,2x+by=15的
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![用代入法解下列方程组,注意事项:不要浪费时间讲道理,(1)x=2分之3,2x-y=8.(2)2x-3y=7,y=3x.(3)m-2n=8,4(m-2n)+n=30.(4)3x+2y=7,5x-4y=-3.(5)2(x+y)-3(x-y)=1,6(x+y)+7(x-y)=51.(1)如果x=7,y=1是方程组3x-ay=16,2x+by=15的](/uploads/image/z/3754613-29-3.jpg?t=%E7%94%A8%E4%BB%A3%E5%85%A5%E6%B3%95%E8%A7%A3%E4%B8%8B%E5%88%97%E6%96%B9%E7%A8%8B%E7%BB%84%2C%E6%B3%A8%E6%84%8F%E4%BA%8B%E9%A1%B9%EF%BC%9A%E4%B8%8D%E8%A6%81%E6%B5%AA%E8%B4%B9%E6%97%B6%E9%97%B4%E8%AE%B2%E9%81%93%E7%90%86%2C%281%29x%3D2%E5%88%86%E4%B9%8B3%2C2x-y%3D8.%EF%BC%882%EF%BC%892x-3y%3D7%2Cy%3D3x.%EF%BC%883%EF%BC%89m-2n%3D8%2C4%28m-2n%29%2Bn%3D30.%284%293x%2B2y%3D7%2C5x-4y%3D-3.%285%292%28x%2By%29-3%28x-y%29%3D1%2C6%28x%2By%29%2B7%28x-y%29%3D51.%EF%BC%881%EF%BC%89%E5%A6%82%E6%9E%9Cx%3D7%2Cy%3D1%E6%98%AF%E6%96%B9%E7%A8%8B%E7%BB%843x-ay%3D16%2C2x%2Bby%3D15%E7%9A%84)
用代入法解下列方程组,注意事项:不要浪费时间讲道理,(1)x=2分之3,2x-y=8.(2)2x-3y=7,y=3x.(3)m-2n=8,4(m-2n)+n=30.(4)3x+2y=7,5x-4y=-3.(5)2(x+y)-3(x-y)=1,6(x+y)+7(x-y)=51.(1)如果x=7,y=1是方程组3x-ay=16,2x+by=15的
用代入法解下列方程组,注意事项:不要浪费时间讲道理,
(1)x=2分之3,2x-y=8.(2)2x-3y=7,y=3x.(3)m-2n=8,4(m-2n)+n=30.(4)3x+2y=7,5x-4y=-3.(5)2(x+y)-3(x-y)=1,6(x+y)+7(x-y)=51.
(1)如果x=7,y=1是方程组3x-ay=16,2x+by=15的解,求a+b的值.
(2)在等式中y=kx+b中,当x=2时,y=10;当x=-2时,y=-2.求k与b的值
(1)x=2分之3,2x-y=8.(2)2x-3y=7,y=3x。(3)m-2n=8,4(m-2n)+n=30.(4)3x+2y=7,5x-4y=-3.(5)2(x+y)-3(x-y)=1,6(x+y)+7(x-y)=51.
用代入法解下列方程组,注意事项:不要浪费时间讲道理,(1)x=2分之3,2x-y=8.(2)2x-3y=7,y=3x.(3)m-2n=8,4(m-2n)+n=30.(4)3x+2y=7,5x-4y=-3.(5)2(x+y)-3(x-y)=1,6(x+y)+7(x-y)=51.(1)如果x=7,y=1是方程组3x-ay=16,2x+by=15的
1,x=3/2 y=2x-8=2*3/2-8=-5
2,2x-3*3x=-7x=7 x=-1 y=-3
3,4*8+n=30 n=-2 m=8+2n=4
4,2y=7-3x 5x-2*2y=5x-2*(7-3x)=11x-14=-3 x=1 y=2
1,3*7-a=16 a=5 2*7+b=15 b=1
2,10=2k+b -2=-2k+b b=4 k=3