教教這7題方程式

1) 3+v/2=v

3 + 1v / 2 = v
3 + 1/2v = v
3 = v - 1/2v
3 = 1/2 v
1/2v = 3
v = 3 x 2/1
v = 3 x 2
v = 6

2) 21-w=5w-3

21 - 1w = 5w - 3
21 + 3 = 5w + 1w
24 = 6w
6w = 24
w = 24 / 6
w = 4

3) 2(5x-1)=3x+5

2 ( 5x - 1 ) = 3x + 5
10x - 2 = 3x + 5
10x - 3x = 5 + 2
7x = 7
x = 7 / 7
x = 1

4) 6(w+3)-(3w-8)=5

6 ( 1w + 3 ) - ( 3w - 8 ) = 5
6w + 18 - 3w + 8 = 5
6w - 3w + 8 + 18 = 5
3w + 26 = 5
3w = 5 - 26
3w = -21
w = -21 / 3
w = -7

5) 3-4(y+2)=y

3 - 4 ( 1y + 2 ) = y
3 - 4y - 8 = y
-4y - 8 + 3 = y
-4y -5 = y
-4y - y = 5
-5y = 5
5y = -5
y = -5 / 5
y = -1

6) 3(4-p)=2(p+3)

3 ( 4 - 1p ) = 2 ( 1p + 3 )
12 - 3p = 2p + 6
12 - 6 = 2p + 3p
6 = 5p
5p = 6
p = 6 / 5
p = 1.2

7) 2[3(c+1)-5]=1

2 [ 3 ( 1c + 1 ) - 5 ] = 1
2 [ 3c + 3 - 5 ] = 1
6c + 6 - 10 = 1
6c - 4 = 1
6c = 1 + 4
6c = 5
c = 5 / 6
c = 0.833

sol
3+v/2=v
6+v=2v
v=6
21-w=5w-3
24=6w
w=4
2(5x-1)=3x+5
10x-2=3x+5
7x=7
x=1
6(w+3)-(3w-8)=5
6w+18-3w+8=5
26+3w=5
21=-3w
w=-7
3-4(y+2)=y
3-4y-8=y
-5=5y
y=-1
2[3(c+1)-5]=1
6(c+1)-10=1
6c+6-10=1
6c=5
c=5/6