中一數~~(10點)

3(x-0.5)-2(x-1.5)=7
(3x-1.5)-(2x-3)=7
3x-1.5-2x-3=7
3x-2x=7+1.5+3
x=11.5

i don"t know the step and answer is it correct , i hope can help you slove the question

2008-10-12 12:37:32 補充：
(3x-1.5)-(2x-3)=7
3x-1.5-2x+3=7
3x-2x=7+1.5-3
x=5.5

sorry ar, the correct answer should be x=5.5 , not x=11.5 ar

詳細：
3(x-0.5)-2(x-1.5)=7
3x-1.5-(2x-3) =7
3x-(2x-3)=7+1.5 <......負負得正..所以會變"+3"
3.x-2x+3=8.5
3x-2x=8.5-3 <......"-3"轉去+答案
1x=5.5 <......3x-2x得1x..1 X x= x
x=5.5 <......答案

簡化 :
3(x-0.5)-2(x-1.5)=7
3x-1.5-(2x-3) =7
3x-2x+3=7+1.5
3x-2x=8.5-3
x=5.5

驗算:
3(5.5-0.5)-2(5.5-1.5)=7
3(5)-2(4)=7
15-8=7
7=7

<完成>

3(x-0.5)-2(x-1.5)=7

3x-1.5-2x+3=7

3x-2x=7+1.5-3

x=5.5

3(x-0.5)-2(x-1.5)=7
3x-1.5-(2x-3) =7
x+1.5 =7
x =5.5