ÉQUATIONS 3ème HELP !!!! a) 6x -5 = 3x+1 b) 7-4x=9-2x c) 3x-4=8-7x d) 5x-1=8x+11 e) 6x-5=10x f) (x+5) + (x-1)=0 g) (-x+8) -(x-1)=0

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a) 6x -5 = 3x+1

6x - 5 - 3x = 3x + 1 - 3x

3x - 5 = 1

3x - 5 + 5 = 1 + 5

3x = 6

3x/3 = 6/3

• x = 2

b) 7-4x=9-2x

7 - 4x + 4x = 9 - 2x + 4x

7 - 9 = 9 + 2x - 9

-2 = 2x

2x/2 = -2/2

• x = -1

c) 3x-4=8-7x

3x - 4 + 4 = 8 - 7x + 4

3x + 7x = 12 - 7x + 7x

10x = 12

10x/10 = 12/10

• x = 6/5

d) 5x-1=8x+11

5x - 1 - 5x = 8x + 11 - 5x

-1 - 11 = 3x + 11 - 11

-12 = 3x

3x/3 = -12/3

• x = -4

e) 6x-5=10x

6x - 5 - 6x = 10x - 6x

-5 = 4x

4x/4 = -5/4

• x = -5/4

f) (x+5) + (x-1)=0

x + 5 + x - 1 = 0

2x + 4 = 0

2x = -4

2x/2 = -4/2

• x = -2

g) (-x+8) -(x-1)=0

-x + 8 - x + 1 = 0

-2x + 9 = 0

-2x + 9 + 2x = 0 + 2x

9 = 2x

2x/2 = 9/2

• x = 9/2

6x -5 = 3x+1 = 6x -3x = +5 +1 = 3x = 6

x = 6/3 = 2

7-4x=9-2x = -4x +2x = -7 +9 = -2x = 2

x = -2/2 = -1 3x -4= 8-7x = 3x +7x = +4 +8 = 10x = 12

x = 12/10 = 6/5

5x -1 = 8x +11 = 5x -8x = 1 +11 = -3x = 12

x = -12/3 = -4

6x -5 = 10x = 6x -10x = +5 = -4x = 5

x = -5/4

(x+5) + (x-1) = 0

x +5 +x -1 = 0 2x + 4 = 0 2x = -4 2x/2 = -4/2 x = -2 (-x+8) -(x-1 )= 0 -x + 8 - x + 1 = 0 -2x + 9 = 0 -2x + 9 + 2x = 0 + 2x = 9 = 2x 2x/2 = 9/2

x= 4,5