Equations

1.) 5(m-1)=3m-7
5m - 5 = 3m - 7
5m -3m = -7 + 5
2m = -2
m = -1

2006-10-16 21:44:01 補充：
2.) 5y-4(3y-2)=-20 5y - 12y + 8 = - 20 -7y = -20 - 8 -7y = -28 y = 4

2006-10-16 21:45:50 補充：
3.) 5(y+4)-6(8+3y)= -2 5y + 20 - 48 - 18y = -2 -13y = -2 -20 + 48 -13y = -22 + 48 -13y = 26 y = -2

2006-10-16 21:47:40 補充：
4.) 7k-(9k-16)=14-(19-k) 7k - 9k + 16 = 14 - 19 + k 7k - 9k -k = 14 - 19 - 16 -3k = -21 k = 7

2006-10-16 21:51:02 補充：
你要記住乖數 : 負負得正, 正正得正, 負正得負, 正負得負.

[1] 5 (m - 1) = 3m - 7
5m - 5 = 3m - 7
2m = -2
m = -1

[2] 5y - 4 (3y - 2) = -20
5y - 12y + 8 = -20
-7y = -28
y = 4

[3] 5 (y + 4) - 6 (8 + 3y) = -2
5y + 4 - 48 - 18y = -2
-13y - 44 = -2
-13y = 42
y = -3

[4] 7k - (9k - 16) = 14 - (19 - k)
7k - 9k + 16 = 14 - 19 + k
-2k + 16 = -5 + k
-3k = -21
k = 7

1)5m-5=3m-7
5m-3m=-7+5
2m=-2
m=-1


2)5y-4(3y-2)=-20
5y-12y+8=-20
-7y=-28
y=4


3)5(y+4)-6(8+3y)=-2
5y+20-48-18y=-2
-13y=-2+28
-13y=26
y=-2


4)7k-(9k-16)=14-(19-k)
7k-9k+16=14-19+k
-2k-k=14-19-16
-3k=-21
k=7

1)5m-5=3m-7
5m-3m=-7+5
2m=-2
m=-1
2)5y-4(3y-2)=-20
5y-12y+8=-20
-7y=-28
y=4
3)5(y+4)-6(8+3y)=-2
5y+20-48-18y=-2
-13y=-2+28
-13y=26
y=-2
4)7k-(9k-16)=14-(19-k)
7k-9k+16=14-19+k
-2k-k=14-19-16
-3k=-21
k=7