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How to do? (Solve the following equations.) 2(z+1) = 3(z-4) 2x = 3(1-x) - (x+1) Can you please explain to me in Chinese? I don't know how to exchange. I can't understand what my Maths teacher talking about in lesson. And thanks for your help!!!
最佳解答:
2(z+1) = 3(z-4) 這是一條一元一次方程 首先你應該將括號除去: 2z+2 = 3z-12 先後移項: 2z-3z = -14 再合井: -z = -14 除去負號: z = 14 2x = 3(1-x) - (x+1) 這是一條一元一次方程 首先你應該將括號除去: 2x = 3-3x-x-1 先後移項: 2x+3x+x = 2 再合井: 6x = 2 x = 1/3
其他解答:
1.) 2(z+1) = 3(z-4) 我們先拆括號 即2乘z加2乘1 和 3乘z減3乘(-4) 2z+2 = 3z-12 把z放在一邊,把數字放在一邊 2z-3z = -12-2 -z = -14 [－,－＝＋負負得正] z = 14 2.) 2x = 3(1-x) - (x+1) 我們先拆括號 即3乘1減3乘x[ 3(1-x) = 3-3x ] [ -(x+1) = -x-1] 2x = 3-3x - x-1 把z放在一邊,把數字放在一邊 2x+3x+x = 3-1 6x = 2 x = 2/6 (約簡) x = 1/3|||||2(z+1) = 3(z-4) 2z+2=3z-12 14=z z=14 2x = 3(1-x) - (x+1) 2x =3-3x-x-1 6x =2 x =1/3|||||2(z+1)=3(z-4) 2z+2=3z-12 2z+2+12=3z 呢度可以用小學所學的方法。移一項先！ 2z+14=3z 3z-2z=14 z=14 途中也可以這樣.(這個方法較快,穩陣就上面的方法) 12+2=3z-2z 將like terms 調在一起，符號沒變。 14=z z=14 2x =3(1-x)-(x+1) 2x =3-3x-x-1 (去括號時，請留意括號前的符號，-(減)的話，括號内的變成+。) 2x =2-4x (3-3x-x-1=3-1-3x-x) 2x+4x=2 (2-4x=2x,所以2x+4x就等於2) x =2/6 x =1/3 其實呢d只係調來調去而已，留意符號的問題，上面也有寫明了。
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