Разложите на множители: ac^4-c^4-ac^2+c^2.

\[ac^{4} - c^{4} - ac^{2} + c^{2} =\]

\[= c^{4}(a - 1) - c^{2}(a - 1) =\]

\[= (a - 1)\left( c^{4} - c^{2} \right) =\]

\[= c^{2}\left( c^{2} - 1 \right)(a - 1) =\]

\[= c²(c - 1)(c + 1)(a - 1)\]