Răspuns :
4 ( x + 5 ) - 5 ( x + 3 ) = x - 5
4x + 20 - 5x - 15 = x - 5
4x - 5x - x = -5 + 15 - 20
-2x = -10
x = -10 / -2 ⇒ x = 5
4x + 20 - 5x - 15 = x - 5
4x - 5x - x = -5 + 15 - 20
-2x = -10
x = -10 / -2 ⇒ x = 5