Odpowiedź :
a) 15 - 3x + 12 = 2x + 6 + 2x
-3x -4x = 6 - 12 - 15
-7x = -21
x= 3
b) Jesli mialo byc tak --> 2x - 4x + 4 = -x - 3
to
2x - 4x + x = -3 - 4
-x = -7
x = 7
a jesli tak --> 2x - (4x + 4) = -x - 3
2x - 4x - 4 = -x - 3
2x - 4x + x = -3 + 4
-x = 1
x = -1