1) $$4a^2 = (2a)^2$$
2) $$a^2b^4 = (ab^2)^2$$
3) $$2a^6 = (\sqrt{2}a^3)^2$$
4) $$\frac{3}{25}b^8 = (\frac{\sqrt{3}}{5}b^4)^2$$
Ответ: 1) $$(2a)^2$$; 2) $$(ab^2)^2$$; 3) $$(\sqrt{2}a^3)^2$$; 4) $$(\frac{\sqrt{3}}{5}b^4)^2$$