Réponse :
on résout :
a. x + 5 = 4 <=> x = 4 -5
<=> x = -1
b. 2x = 3 <=> x = 3/2
c. 4x - 12 = 0 <=> 4x = 12
<=> x = 12/4
<=> x = 3
d. 5x - 19 = 24x - (3x +13) <=> 5x - 19 = 24x - 3x -13
<=> 5x -19 = 21x -13
<=> 21x -5x = -19 +13
<=> 16x = -6
<=> x = -6/16
<=> x = -3/8
e. 5x + 1 = 2x + 19 <=> 5x -2x = 19 -1
<=> 3x = 18
<=> x = 18/3
<=> x = 6
f. 5 + 4h = 0 <=> 4h = -5
<=> h = -5/4
g. (5x-3)(6+x) = 0
les solutions a l'équation précédente sont
5x -3 = 0 ou 6+x = 0
5x = 3 x = -6
x = 3/5
l'ensemble S des solutions l'équation (5x-3)(6+x) = 0
est S= {-6; 3/5}
h. 2-3t = 0 <=> -3t = -2
<=> t = -2 / (-3)
<=> t = 2/3
i. (3/2)x = 7/4 <=> x = (7/4) * (2/3)
<=> x = 7/6
j. 2x + (4+3x)/5 = 2 - (x-6)/10 <=> (20x + 2(4+3x))/10 = (20 - (x-6))/10
<=> (20x + 2(4+3x) - (20 - (x-6)))/10 = 0
<=> (20x + 2(4+3x) - (20 - (x-6))) =0
<=> 20x +8 +6x -(20 -x +6) =0
<=> 26x +8 -20 +x - 6 = 0
<=> 27x -18 = 0
<=> x = 18/27
<=> x = 2/3
k. 6 +2(8+6x) - 9(3x +4) = 0 <=> 6 + 16 + 12x -27x -36 =0
<=> -15x -14 =0
<=> -15x = 14
<=> x = -14/15
m. (3x -1) + (7-x) = 0 <=> 3x - 1 + 7 - x= 0
<=> 2x +6 =0
<=> x = -6/2
<=> x = -3
j'espère avoir aidé.
