Form 1 question

2007-10-11 1:58 am
Help me please!!!

3(x-0.5) - 2(x-4.5) =7
x = ?

How to do it? Can you please help me and explain it to me in Chinese? I don't know what is my Maths teacher talking about. I really don't understand.

Thanks for your help!!~

回答 (3)

2007-10-11 2:35 am
✔ 最佳答案
首先 要張個3 同個 2 乘入去個括號d野
3x - 3乘0.5 - 2x -( -2乘4.5) = 7
負負得正 變左 3x - 1.5 - 2x + 9 = 7
跟住就計啦 x + 0.5 = 7
x = -0.5

想check數 就將 個 -0.5低返去 3(x-0.5) - 2(x-4.5) =7 呢到
咁就得架啦
參考: me
2007-10-12 5:07 am
3x(-1.5)-2x*9=7
-4.5-2x*9=7
81x=7
x=7/81
x=0.09
2007-10-11 2:40 am
3(x-0.5) - 2(x-4.5) =7
3x-1.5 - 2x+9=7<--將3 與 2 放入括弧內
我們得到 3x=1.5 以及 -2x+9<--因為負負得正,是+9 不是-9
x+7.5=7<--做加減數
x+7.5-7.5=7-7.5<--加進-7.5在兩邊
x=-0.5
參考: Maths. Knowledge


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