13) (a) as = a16 a2n

13) $$\frac{(a^5)^3 \cdot a^5}{a^{2n}} = a^{16}$$ $$\frac{a^{15} \cdot a^5}{a^{2n}} = a^{16}$$ $$\frac{a^{20}}{a^{2n}} = a^{16}$$ $$a^{20 - 2n} = a^{16}$$ Следовательно, $$20 - 2n = 16$$ $$-2n = 16 - 20$$ $$-2n = -4$$ $$2n = 4$$ $$n = 4 : 2$$ $$n = 2$$

Ответ: 2