數學中一方程

Q1: 5(y+4)-6(8+3y)= -2 y=?
5y + 20 -48 -18y = -2
-13y = 26
y = -2

Q2. 7k-(9k-16)=14-(19-k) k=?
7k - 9k + 16 = 14 - 19 + k
-2k +16 = -5 + k
-3k = -21
k = 7

Q3. 3[4(2.5-q)+1]=13-2q q=?
3[10 - 4q + 1] = 13 - 2q
33 - 12q = 13 - 2q
-10q = - 20
q = 2


Q4. 2[p-2(p+1)]-1=8p+25 p=?
2[p-2p-2]-1=8p+25
2[-p-2]-1=8p+25
-2p-4-1=8p+25
-10p=30
p=-3

1. 5y + 20 - 48 - 18y = -2
-13y = -2 + 28
-13y = 26
y = -2

2. 7k - 9k +16 = 14 - 19 + k
-2k + 16 = k - 5
3k = 21
k = 7

3. 3(10 - 4q + 1) = 13 - 2q
27 - 4q = 13 - 2q
14 = 2q
q = 7

4. 2(p - 2p - 2) - 1 = 8p + 25
2(-p -2) -1 = 8p + 25
-2p + 4 - 1 = 8p + 25
10p = 22
p = 2.2

1)y = -2

2)k = 7

3)q = 2

4) p=-3

Q1: 5(y+4)-6(8+3y)= -2 y=?

5y+20-48-18y=-2
5y-18y=-2+48-20
-13y=26
y=-2

Q2. 7k-(9k-16)=14-(19-k) k=?

7k-9k+16=14-19+k
7k-9k-k=14-19-16
-10k=-21
k=2.1

Q3. 3[4(2.5-q)+1]=13-2q q=?

3(10-q+1)=13-2q
30-3q+3=13-2q
-3q+2q=13-30-3
-q=-20
q=20


Q4. 2[p-2(p+1)]-1=8p+25 p=?


2(p-2p-2)-1=8p+25
2p-4p-4-1=8p+25
2p-4p-8p=25+4+1
-10=30
p=-3

2006-10-30 20:29:56 補充：
Q2. 7k-(9k-16)=14-(19-k) k=?7k -9k 16 = 14 - 19 k-2k 16 = -5 k-3k = -21k = 7

Q1:
5y+20-48-18y=-2
-13y-28=-2
-13y=26
y=26除-13

Q2:
7k-(9k-16)=14-(19-k)
7k-9k+16=14-19+k
-3k=-21
k=7

Q3:
3[4(2.5-q)+1]=13-2q
3[10-4q+1]=13-2q
30-12q+3=13-2q
20=10q
q=2

2006-10-30 20:11:52 補充：
Q1計少了~不好意思..答案是-2Q4:2[p-2(p 1)]-1=8P 252[p-2p-2]-1=8p 252p-4p-5=8p 25-10p=30p=-3

Q1. - y = -2
Steps:
5y + 20 - 48 - 18 y = -2
-13y - 28 = -2
-13y = 26
y = -2

Q2. - k = 7
Steps:
7k -9k + 16 = 14 - 19 + k
-2k + 16 = -5 + k
-3k = -21
k = 7

Q3 - q = 2
12(2.5-q) + 3 = 13 - 2q
30 - 12q + 3 = 13 - 2q
-10q = -20
q = 2

Q4. - p = -3
2p - 4(p+1) - 1 = 8p + 25
2p - 4p - 4 - 1 = 8p + 25
-2p - 5 = 8p + 25
-10p = 30
p = -3

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