a) $$(4x^3)^5 = 4^5 \cdot (x^3)^5 = 1024x^{3\cdot 5} = 1024x^{15}$$
в) $$(\frac{1}{5}a^7b^4)^2 = (\frac{1}{5})^2 \cdot (a^7)^2 \cdot (b^4)^2 = \frac{1}{25}a^{7\cdot 2}b^{4\cdot 2} = \frac{1}{25}a^{14}b^8$$
г) $$(-x^2y^5z)^7 = (-1)^7 \cdot (x^2)^7 \cdot (y^5)^7 \cdot z^7 = -x^{2\cdot 7}y^{5\cdot 7}z^7 = -x^{14}y^{35}z^7$$
Ответ: a) $$1024x^{15}$$, в) $$\frac{1}{25}a^{14}b^8$$, г) $$-x^{14}y^{35}z^7$$