Aidez moi pour les exo 7 8 16 17! 20 points !

Exercice 7

a) 3x + 1 = 5x - 9
<=> 3x - 5x = -9 - 1
<=> -2x = -10
<=> 2x = 10
<=> x = 5
S={5}

b) 3x + 4 = 15x - 4
<=> 3x - 15x = -4 -4
<=> -12x = -8
<=> 12x = 8
<=> x = 8/12
<=> x = 2/3
S={2/3}

c) x + 4 = -x + 10
<=> x + x = 10 - 4
<=> 2x = 6
<=> x = 3
S={3}

Exercice 8

a) 6x + 4 = 3x - 8
<=> 6x - 3x = -8 - 4
<=> 3x = -12
<=> x = -12/3
S={-4}

b) 3x - 5 = 2x + 4
<=> 3x - 2x = 4 + 5
<=> x = 9
S={9}

c) -2x + 3 = 3x + 18
<=> -2x - 3x = 18 - 3
<=> -5x = 15
<=> 5x = -15
<=> x = -3
S={-3}

d) 5x + 3 = 2x - 4
<=> 5x - 2x = -4 - 3
<=> 3x = -7
<=> x = -7/3
S={-7/3}

e= 2x - 3 = -3x + 4
<=> 2x + 3x = 4 + 3
<=> 5x = 7
<=> x = 7/5
S={7/5}

Exercice 17

1) 2x + 4 = x - 2
<=> x + 4 = -2
<=> x = -6

2) S={-6}