Разложите на множители: c^2(3a-7c)-c^2(5a+3c).

\[c^{2}(3a - 7c) - c^{2}(5a + 3c) =\]

\[= c^{2}\left( 3a - 7c - (5a + 3c) \right) =\]

\[= c^{2}(3a - 7c - 5a - 3c) =\]

\[= c^{2}( - 2a - 10c) = - 2c^{2}(a + 5c).\]