幫下我~唔識ar.....(數學叻既請入)

1. 3(x-0.5)-2(x-4.5)=7
3x-1.5-2x+9=7
x+7.5=7
x=0.5

2. 6[2(2-y)-3y]=24
6(4-2y-3y)=24
6(4-y)=24
4-y=4
y=0

3. 9(2a-1)=3[4(1+2a)-5]-8a
18a-9=3(4+8a-5)-8a
18a-9=3(8a-1)-8a
18a-9=24a-3-8a
18a-9=16a-3
2a=6
a=3

1.......3(x-0.5)-2(x-4.5)=7
...............3x-1.5-2x+9=7
........................x+7.5=7
..............................x=7-7.5
..............................x=-0.5
驗算：
..3(-0.5-0.5)-2(-0.5-4.5)
=3x-1+.-2x-5
=.-3+10
=7

1......6〔2(2-y)-3y〕=24
....6 〔2(2-y)-3y〕/6=24/6
..........〔2(2-y)-3y〕=4
...................4-4y-3y=4
....................-4y-3y=4-4
...........................-y=0
驗算：
..6x〔2x(2-0)-3x0〕
=6x〔4-0-0〕
=6x4
=24

3............9(2a-1)=3〔4(1+2a)-5〕-8a
................18a-9=3〔4+8a-5〕-8a
................18a-9=3〔8a-1〕-8a
................18a-9=24a-3-8a
................18a-9=16a-3
.............18a-16a=.-3+9
........... .......2a=6
.......................a=6/2.
.......................a=3
驗算：
左..9x(2x3-1)
...=9x5
...=45
右..3x〔4x(1+2x3)-5〕-8x3
...=3x〔4x7-5〕-24
...=3x23-24
...=69-24
...=45
...................a=1

2007-11-14 22:54:36 補充：
最後的.......a=1唔知點解打多左，它不是答案

1. 3(x-0.5)-2(x-4.5)=7
3x-1.5-2x+9=7
x-1.5+9=7
x=1.5

1. 3(x-0.5)-2(x-4.5)=7
2. 6[2(2-y)-3y]=24
3. 9(2a-1)=3[4(1+2a)-5]-8a

3同(之間冇加減乘除? IS 乘AR

3(x-0.5)-2(x-4.5)=7
3X-1.5-2X+9=7
3X-2X=7-9+1.5
X=0.5

6[2(2-y)-3y]=24
6[4-2Y-3Y]=24
24-12Y-18Y=24
-30Y=0
Y=0

9(2a-1)=3[4(1+2a)-5]-8a
18A-9=12+24A-15-8A
18A+8A-24A=12-15+9
2A=6
A=3

1. 3x-1.5-2x+9=7
3x-2x =7-9+1.5
x =-0.5

2. 6[4-2y-3y] = 24
4-5y =4
-5y =0
y =0

3. 18a-9= 3[4+8a-5]-8a
6a-3 = 4+8a-5-8a
6a =3+4-5
a =2/6
=1/3

2007-11-14 21:52:40 補充：
3. 18a-9 = 3[4+8a-5]-8a 26a-9 = 3[8a-1] 26a-9 = 24a-3 2a =9-3 2a =6 a =3

唔明你問咩?如一題: 3(x-0.5)-2(x-4.5)=7
3同(之間冇加減乘除?