Odpowiedź :
(a + b + c) - (a - b - c) =
= a + b + c - a + b + c = 2b + 2c
(x² + 2x) - (x² + 6x) =
= x² + 2x - x² - 6x = -4x
e) [tex](a+b+c)-(a-b-c)=\\=\not a+b+c-\not a+b+c=\\=\boxed{2b+2c}[/tex]
f) [tex](x^2+2x)-(x^2+6x)=\\=\not x^2+2x-\not x^2-6x=\\=\boxed{-4x}[/tex]