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1. 15-(r-6)=6-(3r+5)
15-r+6=6-3r-5
2r=-20
r=-10

2. 7(2x-3)-3(4x+1)=4-10(2-x)
14x-21-12x-3=4-20+10x
2x-24=-16+10x
-8=8x
x=-1

3. 3[4d-5(4-d)]=4(7-3d)-10
3(4d-20+5d)=28-12d-10
12d-60+15d=18-12d
12d+15d+12d=18+60
39d=78
d=2

4. x/2 + x+2/7 =x-4
14( x/2 + x+2/7) =14(x-4)
7x+14x+4 =14x-56
7x=-60
x=-60/7

5. x-1/5 + 4-x/2 -2=0
10( x-1/5 + 4-x/2 -2)=0x10
10x-2+40-5x-20=0
5x=-18
x=-18/5

6. (3y-5)+(y-5)=50
3y-5+y-5=50
4y=60
y=15

1. 15-(r-6)=6-(3r+5)
15-r+6=6-3r-5
-r+3r=-15-5
2r=-20
r=-10

2. 7(2x-3)-3(4x+1)=4-10(2-x)
14x-21-12x-3=4-20+10x
2x-24=-16+10x
2x-10x=-16+24
-8x=8
x=-1

3. 3[4d-5(4-d)]=4(7-3d)-10
3[4d-20+5d]=28-12d-10
9d-20=6-4d
9d+4d=6+20
13d=26
d=2


4. x/2 + x+2/7 =x-4
x/2+2/7=-4
x/2=-4-2/7
x/2=(-28-2)/7
x/2=-30/7
x=-60/7

5. x-1/5 + 4-x/2 -2=0
10(x-1/5+4-x/2-2)=0
10x-2+40-5x-20=0
5x+18=0
5x=-18
x=-18/5

2009-12-14 16:16:36 補充

6. (3y-5)+(y-5)=50
4y-10=50
4y=50+10
4y=60
y=15

1. 15-(r-6)=6-(3r+5)
15-r+6=6-3r-5
21-r=1-3r
2r=1-21
2r=-20
r=10

2. 7(2x-3)-3(4x+1)=4-10(2-x)
14x-21-12x-3=4-10+20x
2x-24=20x-6
-18x=18
x=-1

3. 3[4d-5(4-d)]=4(7-3d)-10
3[4d-20+5d]=28-12d-10
3[9d-20]=18-12d
27d-60=18-12d
39d=78
d=2

4. x/2 + (x+2)/7 =x-4
同乘以14
7x+2(x+2)=14x-56
7x+2x+4=14x-56
9x+4=14x-56
-7x=-60
x=60/7

5.(x-1)/5 + (4-x)/2 -2=0
乘10
2(x-1)+5(4-x)-20=0
2x-2+20-5x-20=0
-3x-2=0
-3x=2
x=-2/3

6. (3y-5)+(y-5)=50
3y-5+y-5=50
4y-10=50
4y=60
y=15

1. 15-(r-6)=6-(3r+5)
15-r+6=6-3r-5
21-r=1-3r
2r=1-21
2r=-20
r=-10
2. 7(2x-3)-3(4x+1)=4-10(2-x)
14x-21-12x-3=4-10+20x
2x-24=20x-6
-18x=18
x=-1
3. 3[4d-5(4-d)]=4(7-3d)-10
3[4d-20+5d]=28-12d-10
3[9d-20]=18-12d
27d-60=18-12d
39d=78
d=2
4. x/2 + (x+2)/7 =x-4
同乘以14
7x+2(x+2)=14x-56
7x+2x+4=14x-56
9x+4=14x-56
-7x=-60
x=60/7
5.(x-1)/5 + (4-x)/2 -2=0
同乘以10
2(x-1)+5(4-x)-20=0
2x-2+20-5x-20=0
-3x-2=0
-3x=2
x=-2/3

6. (3y-5)+(y-5)=50
3y-5+y-5=50
4y-10=50
4y=60
y=15