$$\vec{a} = (2; 4) \Rightarrow -\vec{a} = (-2; -4)$$;
$$\vec{b} = (-2; 0) \Rightarrow -\vec{b} = (2; 0)$$;
$$\vec{c} = (0; 0) \Rightarrow -\vec{c} = (0; 0)$$;
$$\vec{d} = (-2; -3) \Rightarrow -\vec{d} = (2; 3)$$;
$$\vec{e} = (2; -3) \Rightarrow -\vec{e} = (-2; 3)$$;
$$\vec{f} = (0; 5) \Rightarrow -\vec{f} = (0; -5)$$.
Ответ: $$\vec{-a} = (-2; -4)$$, $$\vec{-b} = (2; 0)$$, $$\vec{-c} = (0; 0)$$, $$\vec{-d} = (2; 3)$$, $$\vec{-e} = (-2; 3)$$, $$\vec{-f} = (0; -5)$$.