45)a.5x+7=2x-2
5x-2x=-2-7
3x=-9
x=-3
b.3y+2=y-10
3y-y=-10-2
2y=-12
y=-6
c.2.5x-1=4+2x
2.5x-2x=4+1
0.5x=5
x=10
d.7x-3=-5x+4
7x+5x=4+3
12x=7
x=7 sur 12 (fraction)
46)a.2t-5=5t+1
2t-5t=1+5
-3t=6
t=-2
b.3-7x=3x+2
-7x-3x=2-3
-10x=-1
x=1 sur 10 (fraction)
c.3t-(1-t)=7
3t-1+t=7
3t+t=7+1
4t=8
t=2
d.2(1-4t)=t+3
2-8t=t+3
-8t-t=3-2
-9t=1
t= - 1 sur 9 (fraction)
47) réponse dans l’image.
