bonsoir
exercice 13
a 17b-6=9b-11
17b-9b=-11+6
8b=-5
b=-5/8=-0.625
b -3b+4=-7b+11
-3b+7b=11-4
4b=7
b=7/4=1.75
c 2b-1=-13b+5
2b+13b=5+1
15b=6
b=6/15=0.4
d -9b+13=15b-5
-9b-15b=-5-13
-24b= -18
b=-18/-24=0.75
exercice 14
a 8x+9=5x+11
8x-5x=11-9
3x= 2
x=2/3
b 5x+17=8x-9
5x-8x=-9-17
-3x=-26
x= 26/3
c 4x-5=11x-2
4x-11x=-2+5
-7x= 3
x=-3/7
d 13x-11=7x+23
13x-7x=23+11
6x=34
x=34/6=17/3
exercice 15
a 5x+3=8x+17
5x-8x=17-3
-3x=14
x=14/-3
b -3x-13=8x-5
-3x-8x=-5+13
-11x= 8
x=8/-11
c 5x-5=17x-11
5x-17x=-11+5
-12x=-6
x=6/12=1/2
d -2.4x+5=7.8x-3
-2.4x-7.8x=-3-5
-10.2x=-8
x= 8/10.2
