Răspuns:
Punctul a)
7x - 7 = 6 - 3 × (x + 1)
7x - 7 = 6 - 3x - 3
7x - 7 = 3 - 3x
7x - 10 = -3x
10x - 10 = 0
10x = 10
x = 10 : 10
x = 1
S = {1}
Punctul c)
x × (x + 1) = x² + 2x + 1
x² + x = x² + 2x + 1
x = 2x + 1
x + 1 = 0
x = -1
S = {-1}
Punctul e)
5 × (1 - 2x) + 1 = 4 × (x + 3) + 8
5 - 10x + 1 = 4x + 12 + 8
6 - 10x = 4x + 20
6 - 14x = 20
14x = 6 - 20
14x = -14
x = -14 : 14
x = -1
S = {-1}