Упростим выражение:
a) $$4 \frac{1}{6}a^8b^5 \cdot \left(-1 \frac{1}{5}a^5b\right)^3 = \frac{25}{6}a^8b^5 \cdot \left(-\frac{6}{5}a^5b\right)^3 = \frac{25}{6}a^8b^5 \cdot \left(-\frac{6^3}{5^3}a^{5 \cdot 3}b^3\right) = \frac{25}{6} \cdot \left(-\frac{216}{125}\right) \cdot a^8 \cdot a^{15} \cdot b^5 \cdot b^3 = -\frac{25 \cdot 216}{6 \cdot 125} a^{8+15}b^{5+3} = -\frac{5 \cdot 36}{1 \cdot 25} a^{23}b^8 = -\frac{180}{25}a^{23}b^8 = -\frac{36}{5}a^{23}b^8 = -7 \frac{1}{5}a^{23}b^8$$
б) $$a^{m+1} \cdot a \cdot a^{3-m} = a^{m+1+1+3-m} = a^{5}$$
Ответ: a) $$-7 \frac{1}{5}a^{23}b^8$$, б) $$a^5$$