Odpowiedź:
f) 5x + (2y + x) = 5x + 2y + x = 6x + 2y
g) 7 - (4x - 6) = 7 - 4x + 6 = 13 - 4x
h) 8x - (2x - 3) = 8x - 2x + 3 = 6x + 3
i) (x + 2) - (-x - 7) = x + 2 + x + 7= 2x + 9
j) (x + 6y) + (2x + 7y) = x + 6y + 2x + 7y = 3x + 13y
