Bonjour,
a.5x-7=8
5x = 8+7 = 15
x= 15/5 = 3
b.-2=18+10y
-2-18 = 10y
-20 = 10y
y = -20/10 = -2
c.7+9y= -29
9y = -29 -7
9y = - 36
y= -36/9 = -4
d.3(x-1)=3
x-1 = 3/3 = 1
x= 1+1 = 2
e. 12 -6x=3/2
12- 3/2 = 6x
24/2 -3/2 = 6x
21/2 = 6x
x= (21/2) /6
x= 21/(6*2)= 21/12
f.5x/3x+1/5 2x/3x-1/5
le signe=?