9(2a-1)=3[4(1+2a)-5]-8a(步驟)

一.
9(2a-1)=3[4(1+2a)-5]-8a
18a-9=3[4+8a-5]-8a
18a-9=12+24a-15-8a
18a+8a-24a=12-15
2a=-3
a= -3/2
其實你第2-5題係唔係冇加括號?
2n-5÷3=n-10÷9果題...係唔係(2n-5)÷3=(n-10)÷9呀?兩樣野黎嫁喎!
二.
2n-5÷3=n-10÷9
2n-5/3+10/9=n
2n-n=5/3+10/9
n=15/9+10/9
n=25/9

2008-10-07 16:40:36 補充：
你答左我...我再計

1.9(2a-1)=3[4(1+2a)-5]-8a
18a-9=3(4+8a-5-8a)
18a-9=-3
18a=6
a=3

2.2n-5÷3=n-10÷9(÷變/即係over)
(2n-5/3)x3=n-10/9 (通分)
6n-15/9=n-10/9
[6n-15/9=n-10/9]x9
6n-n=-10+15
5n=5
n=1

3.x-1÷2=x+1÷3+1 同上
(x-1/2)x2=x+1/4
[2x-2/4=x+1/4]x4
2x-x=1+2
x=3

4.A÷3=9+8(A-4/3)
A/3 =9+8A-96/3
[A/3 =(27+24A-96)/3]x3
A =-69+24A
69=23A
A=3

5.y除4-2(y-9)除3+5y+8除6
y/4-2(y-9)/3+5y+8/6 (唔知點計)

2008-10-07 18:25:06 補充：
y/4-2(y-9)/3=5y+8/6
[3y-8y+36]/12=[60y+16]/12
-5y+36=60y+16
65y=20
y=4/13 (咁都可以計既~)

2008-10-07 18:28:28 補充：
以上都計錯~幫唔到你€

1.9(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


2.2n-5除3=n-10除9

2n-5/3 =n-10/9
18n-15 =9n-10
9n =5
n =5/9



3.x-1除2=x+1除3+1

x-1/2 =x+1/3+1
6x-3 =6x+2+6
0 = ..... 計算不到, 是否有錯漏?


4.A除3=9+8(A-4分3)

A/3 =9+8(A-3/4)
A/3 =9+8A-6
A =9+24A
A = -9/23

5.y除4-2(y-9)除3+5y+8除6 這一條, 沒有等號的嗎?

y/4-2(y-9)/3+5y+8/6