\[\boxed{\text{54\ (54).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
Пояснение.
Решение.
\[\textbf{а)}\ 4x - x^{3} = x\left( 4 - x^{2} \right) =\]
\[= x(2 - x)(2 + x)\]
\[\textbf{б)}\ a^{4} - 169a^{2} =\]
\[= \left( a^{2} - 13a \right)\left( a^{2} + 13a \right) =\]
\[= a(a - 13) \cdot a(a + 13) =\]
\[= a^{2}(a - 13)(a + 13)\]
\[\textbf{в)}\ c^{3} - 8c^{2} + 16c =\]
\[= c\left( c^{2} - 8c + 16 \right) = c(c - 4)^{2} =\]
\[= c(c - 4)(c - 4)\]