б) $$(1,5a^2b^3)^2 = (1,5)^2 \cdot (a^2)^2 \cdot (b^3)^2 = 2,25a^{2\cdot 2}b^{3\cdot 2} = 2,25a^4b^6$$.
Ответ: $$2,25a^4b^6$$