Докажите неравенство: (a+5)(a-2)>(a-5)(a+8).

\[(a + 5)(a - 2) > (a - 5)(a + 8)\]

\[a^{2} + 3a - 10 > a^{2} + 3a - 40\]

\[a^{2} + 3a - 10 - a^{2} - 3a + 40 > 0\]

\[30 > 0 \Longrightarrow верно.\]