中一數學題,急用,十五點

q1. 3x+5=-16
3x = -16 - 5
3x = -21
x = -21/3
x = -7

q2. 4-5y=-26
4+36 = 5y
40 = 5y
40/5 = y
8 = y
y = 8

q3. 7分之5-y=3
5/7 - 3 = y
5/7 - 21/7 = y
-16/7 = y
y = -16/7

q4. 2(p-6)=18
p - 6 = 18/2
p = 9 + 6
p = 15

q5. 5-九分之x=3
5 - x/9 = 3
5 - 3 = x/9
2 = x/9
2 * 9 = x
x = 18

q6. 6(4x+11)=-30
4x + 11 = -30/6
4x = -5 - 11
x = -16/4
x = -4

q7. 0.4n+2.9=4.1
0.4n = 4.1 - 2.9
n = 1.2/0.4
n = 3

q8. 13分之6y-35=-11
6y/13 = -11 + 35
6y = 24 * 13
y = 312/6
y = 52

q9. 七分之4(5x-1)=8
4(5x - 1) = 8 * 7
5x - 1 = 56/4
5x = 14 + 1
x = 15/5
x = 3

2011-12-03 21:24:20 補充：
q2. 計錯，應該是 :

4-5y=-26
4+26 = 5y
30 = 5y
30/5 = y
6 = y
y = 6

2011-12-05 10:49:38 補充：
1/4 + n/5 = 1/20
5/20 + 4n/20 = 1/20
5 + 4n = 1
4n = 1 - 5
4n = -4
n = -1

q1. 3x+5=-16
3x = -16 - 5
3x = -21
x = -21/3
x = -7

q2. 4-5y=-26
4+36 = 5y
40 = 5y
40/5 = y
8 = y
y = 8

q3. 7分之5-y=3
5/7 - 3 = y
5/7 - 21/7 = y
-16/7 = y
y = -16/7

q4. 2(p-6)=18
p - 6 = 18/2
p = 9 + 6
p = 15

q5. 5-九分之x=3
5 - x/9 = 3
5 - 3 = x/9
2 = x/9
2 * 9 = x
x = 18

q6. 6(4x+11)=-30
4x + 11 = -30/6
4x = -5 - 11
x = -16/4
x = -4

q7. 0.4n+2.9=4.1
0.4n = 4.1 - 2.9
n = 1.2/0.4
n = 3

q8. 13分之6y-35=-11
6y/13 = -11 + 35
6y = 24 * 13
y = 312/6
y = 52

q9. 七分之4(5x-1)=8
4(5x - 1) = 8 * 7
5x - 1 = 56/4
5x = 14 + 1
x = 15/5
x = 3

q1
3x=-21
X=-7
q2.
30=5y
y=6
q3.
y=-4.2
q4.
(p-6)=9
P=15
q5.
九分之x=2
X=18
q6.
(4x+11)=-5
4x=-26
X=4
q7.
0.4n=1.2
n=3
q8.
13分之6y=24
y=52
q9.
(5x-1)=14
5X=15
X=3