Răspuns :
a) 3x + 8 = 14
3x = 14 - 8
3x = 6
x = 6 : 3
x = 2
S = {2}
b) 2x - 3 = x + 2
x - 3 = 2
x = 2 + 3
x = 5
S = {5}
c) 3x + 2 = x - 6
2x + 2 = -6
2x = -6 - 2
2x = -8
x = -8 : 2
x = -4
S = {-4}
e) 3x - 8 = x + 4
2x - 8 = 4
2x = 4 + 8
2x = 12
x = 12 : 2
x = 6
S = {6}
f) 3x - 11 = x - 23
2x - 11 = -23
2x = -23 + 11
2x = -12
x = -12 : 2
x = -6
S = {-6}
g) 4x + 5 = 2x + 13
2x + 5 = 13
2x = 13 - 5
2x = 8
x = 8 : 2
x = 4
S = {4}
h) 5x - 9 = 3x + 1
2x - 9 = 1
2x = 1 + 9
2x = 10
x = 10 : 2
x = 5
S = {5}
i) 3x + 11 = -10
3x = -10 - 11
3x = -21
x = -21 : 3
x = -7
S = {-7}
j) -7x + 19 = -16
-7x = -16 - 19
-7x = -35
7x = 35
x = 35 : 7
x = 5
S = {5}
k) 5(x + 3) = -20
5x + 15 = -20
5x = -20 - 15
5x = -35
x = -35 : 5
x = -7
S = {-7}
m) -6x + 22 = -20
-6x = -20 - 22
-6x = -42
6x = 42
x = 42 : 6
x = 7
S = {7}
n) -11x - 91 = 30
-11x = 30 + 91
-11x = 121
x = 121 : -11
x = -11
S = {-11}
o) 4x + 15 = -5
4x = -5 - 15
4x = -20
x = -20 : 4
x = -5
S = {-5}