Résoudre chaque equation

exercice24)
a) 3(x+7)=4
3x+21=4
3x=4-21
3x=-17
x=-17/3

b)2(2-y)=-6
4-2y=-6
-2y=-6-4
-2y=-10
y=-10/-2
y=5

c)-3+a=7(2a-1)
-3+a=14a-7
a-14a=-7+3
-13a=-4
a=-4/-13
a=4/13

d)-3(2t+1)=-3(t-2)
-6t-3=-3t+6
-6t+3t=6+3
-3t=3
t=-1

exercice25)

a)2(x+1)=3(x-1)
2x+2=3x-3
2x-3x=-3-2
-x=-5
x=5

b)3(2-3y)=-(y-2)
6-9y=-y+2
-9y+y=2-6
-8y=-4
y=4/8
y=0,5

c)-2(a-1)=4(2a+1)
-2a+2=8a+4
-2a-8a=4-2
-10a=2
a=-2/10
a=-0,2