方程 (20分)

1. 2x-3/4=2x+3
2x-3=4(2x+3)
2x-3=8x+12
2x=8x+15
-6x=15
x= -(15/6)

2. 5x-3/4=7x+1/3
3(5x-3)=4(7x+1)
15x-9=28x+4
-13=13x
x= -1

3. x-4/2+x-3= -5
x-4/2= -5-x+3
x-4/2= -2-x
x-4=2(-2-x)
x-4= -4-2x
3x=0
x=0

1. 2x - 3/4 = 2x+3
8x - 3 = 4(2x+3)
8x - 3 = 8x + 12
No solution

2. 5x - 3/4 = 7x + 1/3
3(20x - 3) = 4(21x + 1)
60x - 9 = 84x + 4
-24x = 13
x = -2.4

3. x - 4/2 + x - 3 = -5
2x - 4/2 = -2
2x = -2 + 2
x = 0

1. 2x-3/4=2x+3
2x-4/3+2x=2x+3+2x
3/4=4x+3
3/4-3=4x+3-3
3/4-12/3=4x
9/12-48/12=4x
-39/12=4x
-39/12 over4=4x over4
-39/48=x
2. 5x-3/4=7x+1/3
5x-9/12=7x+4/12
5x-9/12-4/12=7x+4/12-4/12
5x-13/12=7x
5x-13/12+5x=7x+5x
13/12=12x
13/12 over12=12x over12
13/144=x
3. x-4/2+x-3=-5
x-2+x-3+5=-5+5
x+x-2-3+5=0
2x=0
2x over2=0 over2
x=0

1. 2x-3/4=2x+3

2x-3 = 8x + 12
-6x = 15
x = -15 /6


2. 5x-3/4=7x+1/3

15x -9 = 28x +4
-13x = -13
x = 1


3. x-4/2+x-3= -5

x-4/2 = -2 - x
x-4 = -4 - 2x
x = 0

1.2x-3/4=2x+3
2x-3/4-2x=2x+3-2x
-3/4 = 3 <<條equation應該唔成立WO,...=.=

2. 5x-3/4=7x+1/3
( 5x-3/4=7x+1/3 )*12
60x - 9 = 84x + 4
-24x = 13
x = -13/24 ....=.=

3. x-4/2+x-3= -5
x - 2 + x -3 = -5
2x = 0
x = 0

應該岩掛=.=|||